他又又来了，c#开源sql解析引擎类库【SqlParser.Net 1.0】正式发布，它可以帮助你简单快速高效的解析和处理sql

news/2025/3/14 7:45:23/文章来源:https://www.cnblogs.com/longshao2024/p/18771377

hi 大家好，我是三合，在过往的岁月中，我曾经想过要写以下这些工具

  1. 写一个通过拦截业务系统所有sql，然后根据这些sql自动分析表与表,字段与字段之间是如何关联的工具，即sql血缘分析工具
  2. 想着动态改写sql，比如给where动态添加一个条件。
  3. 写一个sql格式化工具
  4. 写一个像mycat那样的分库分表中间件
  5. 写一个sql防火墙，防止出现where 1=1后没有其他条件导致查询全表
  6. 写一个数据库之间的sql翻译工具，比如把sqlserver的sql自动翻译为oracle的sql

但是无一例外，都失败了，因为要实现以上这些需求，都需要一个核心的类库，即sql解析引擎，遗憾的是，我没有找到合适的，这是我当初寻找的轨迹

  1. 我发现了tsql-parser,但他只支持sql server，所以只能pass。
  2. 然后我又发现了SqlParser-cs,
    他的语法树解析出来像这样，
JsonConvert.SerializeObject(statements.First(), Formatting.Indented)
// Elided for readability
{"Query": {"Body": {"Select": {"Projection": [{"Expression": {"Ident": {"Value": "a","QuoteStyle": null}}}...

额，怎么说呢，这语法树也太丑了点吧，同时非常难以理解，跟我想象中的完全不一样啊，于是也只能pass。

  1. 接下来我又发现了另外一些基于antlr来解析sql的类库，比如SQLParser,因为代码是antlr自动生成的，比较难以进行手动优化，所以还是pass。

  2. 最后我还发现了另外一个gsp的sqlparser,但它是收费的，而且巨贵无比，也pass。

找了一圈下来，我发现符合我要求的类库并不存在，所以我上面的那些想法，也一度搁浅了，但每一次的搁浅，都会使我内心的不甘加重一分，终于有一天，我下定决心，自己动手，丰衣足食，所以最近花了大概3个月时间，从头开始写了一个sql解析引擎，包括词法解析器到语法分析器，不依赖任何第三方组件，纯c#代码，在通过了156个各种各样场景的单元测试以及各种真实的业务环境验证后，今天它SqlParser.Net1.0.0正式发布了，本项目基于MIT协议开源，有以下优点，

  1. 支持5大数据库，oracle，sqlserver，mysql，pgsql以及sqlite。
  2. 极致的速度，解析普通sql，时间基本在0.3毫秒以下，当然了,sql越长，解析需要的时间就越长。
  3. 文档完善，众所周知，我三合的开源项目，一向是文档齐全且简单易懂，做到看完就能上手，同时，我也会根据用户的反馈不断的补充以及完善文档。
  4. 代码简洁易懂

SqlParser.Net存在的意义

SqlParser.Net是一个免费，功能全面且高性能的sql解析引擎类库，它可以帮助你简单快速高效的解析和处理sql。

Getting Started

接下来，我将介绍SqlParser.Net的用法

通过Nuget安装

你可以运行以下命令在你的项目中安装 SqlParser.Net 。

PM> Install-Package SqlParser.Net

支持框架

netstandard2.0

从最简单的demo开始

让我们一起看一个最简单的select语句是如何解析的

var sql = "select * from test";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()}},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test"}}}
};

以上面为例子，抽象语法树的所有叶子节点均为sqlExpression的子类，且各种sqlExpression节点可以互相嵌套，组成一颗复杂无比的树，其他sql解析引擎还分为statement和expression，我认为过于复杂，所以全部统一为sqlExpression，顶级的sqlExpression总共分为4种，

  1. 查询语句(SqlSelectExpression)
  2. 插入语句(SqlInsertExpression)
  3. 删除语句(SqlDeleteExpression)
  4. 更新语句(SqlUpdateExpression)

这4种顶级语句中，我认为最复杂的是查询语句，因为查询组合非常多，要兼容各种各样的情况，其他3种反而非常简单。现阶段，sqlExpression的子类一共有38种，我将在下面的演示中，结合例子给大家讲解一下。

1. Select查询语句

如上例子，SqlSelectExpression代表一个查询语句，SqlSelectQueryExpression则是真正具体的查询语句，他包括了

  1. 要查询的所有列（Columns字段）
  2. 数据源(From字段)
  3. 条件过滤语句(Where字段)
  4. 分组语句（GroupBy字段）
  5. 排序语句(OrderBy字段)
  6. 分页语句(Limit字段)
  7. Into语句(sql server专用，如SELECT id,name into test14 from TEST t)
  8. ConnectBy语句（oracle专用，如SELECT LEVEL l FROM DUAL CONNECT BY NOCYCLE LEVEL<=100）
  9. WithSubQuerys语句，公用表表达式，即CTE

其中Columns是一个列表，他的每一个子项都是一个SqlSelectItemExpression，他的body代表一个逻辑子句，逻辑子句的值，可以为以下这些

  1. 字段，如name，
  2. 二元表达式，如t.age+3
  3. 函数调用，如LOWER(t.NAME)
  4. 一个完整的查询语句，如SELECT name FROM TEST2 t2

包括order by，partition by，group by,between,in,case when后面跟着的都是逻辑子句，这个稍后会演示，在这个例子中，因为是要查询所有列，所以仅有一个SqlSelectItemExpression，他的body是SqlAllColumnExpression（代表所有列），From代表要查询的数据源，在这里仅单表查询，所以From的值为SqlTableExpression（代表单表），表名是一个SqlIdentifierExpression，即标识符表达式，表示这是一个标识符，在SQL中，标识符（Identifier）是用于命名数据库对象的名称。这些对象可以包括表、列、索引、视图、模式、数据库等。标识符使得我们能够引用和操作这些对象，在这里，标识符的值为test，表示表名为test。

1.1 查询返回列的各种情形

1.1.1 查询指定字段

var sql = "select id AS bid,t.NAME testName  from test t";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlIdentifierExpression(){Value = "id",},Alias = new SqlIdentifierExpression(){Value = "bid",},},new SqlSelectItemExpression(){Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "NAME",},Table = new SqlIdentifierExpression(){Value = "t",},},Alias = new SqlIdentifierExpression(){Value = "testName",},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test",},Alias = new SqlIdentifierExpression(){Value = "t",},},},
};

在上面这个例子中，我们指定了要查询2个字段，分别是id和t.NAME，此时Columns列表里有2个值，
第一个SqlSelectItemExpression包含了

  1. 主体，即body字段，在本例子中他的值是一个SqlIdentifierExpression表达式，值为id，表示列名为id，
  2. 别名，即Alias字段，在本例子中他也是一个SqlIdentifierExpression，值为bid，代表列别名为bid，

第二个SqlSelectItemExpression的body里是一个SqlPropertyExpression，代表这是一个属性表达式，SqlPropertyExpression它包含了

  1. 表名，即Table字段，值为t，即表名为t
  2. 属性名，即Name字段，值为Name，即属性名为name

合起来则代表t表的name字段，而第二个SqlSelectItemExpression也有列别名，即testName，这个查询也是单表查询，但SqlTableExpression他多了一个Alias别名字段，即表示，表别名为t。

1.1.2 查询列为二元表达式的情况

var sql = "select 1+2 from test";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlBinaryExpression(){Left = new SqlNumberExpression(){Value = 1M,},Operator = SqlBinaryOperator.Add,Right = new SqlNumberExpression(){Value = 2M,},},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test",},},},
};

在这个例子中，要查询的字段的值为一个二元表达式SqlBinaryExpression，他包含了

  1. 左边部分，即Left字段，值为一个SqlNumberExpression，即数字表达式，它的值为1
  2. 右边部分，即Right字段，值为一个SqlNumberExpression，即数字表达式，它的值为2
  3. 中间符号，即Operator字段，值为add，即加法

这个例子证明了，SqlSelectItemExpression代表一个逻辑子句，而不仅仅是某个字段。

1.1.3 查询列为字符串/数字/布尔值的情况

var sql = "select ''' ''',3,true FROM test";
var sqlAst = DbUtils.Parse(sql, DbType.MySql);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlStringExpression(){Value = "' '"},},new SqlSelectItemExpression(){Body = new SqlNumberExpression(){Value = 3M,},},new SqlSelectItemExpression(){Body = new SqlBoolExpression(){Value = true},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test",},},},
};

在这个例子中，要查询的3个字段为字符串，数字和布尔值，字符串表达式即SqlStringExpression，body里即字符串的值' '，数字表达式即SqlNumberExpression，值为3，布尔表达式即SqlBoolExpression，值为true；

1.1.4 查询列为函数调用的情况

1.1.4.1 简单的函数调用
var sql = "select LOWER(name)  FROM test";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlFunctionCallExpression(){Name = new SqlIdentifierExpression(){Value = "LOWER",},Arguments = new List<SqlExpression>(){new SqlIdentifierExpression(){Value = "name",},},},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test",},},},
};

在这个例子中，要查询的表达式是一个函数调用，函数调用表达式即SqlFunctionCallExpression，它包含了

  1. 函数名，即Name字段，值为LOWER，
  2. 函数参数列表，即Arguments字段，列表里只有一个值，即函数只有一个参数，且参数的值为name
1.1.4.2 带有over子句的函数调用
var sql = "SELECT t.*, ROW_NUMBER() OVER ( PARTITION BY t.ID  ORDER BY t.NAME,t.ID) as rnum FROM TEST t";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "*",},Table = new SqlIdentifierExpression(){Value = "t",},},},new SqlSelectItemExpression(){Body = new SqlFunctionCallExpression(){Name = new SqlIdentifierExpression(){Value = "ROW_NUMBER",},Over = new SqlOverExpression(){PartitionBy = new SqlPartitionByExpression(){Items = new List<SqlExpression>(){new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "ID",},Table = new SqlIdentifierExpression(){Value = "t",},},},},OrderBy = new SqlOrderByExpression(){Items = new List<SqlOrderByItemExpression>(){new SqlOrderByItemExpression(){Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "NAME",},Table = new SqlIdentifierExpression(){Value = "t",},},},new SqlOrderByItemExpression(){Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "ID",},Table = new SqlIdentifierExpression(){Value = "t",},},},},},},},Alias = new SqlIdentifierExpression(){Value = "rnum",},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "TEST",},Alias = new SqlIdentifierExpression(){Value = "t",},},},
};

在这个例子中，SqlFunctionCallExpression它除了常规字段外，还包含了Over子句，具体有以下这些

  1. 函数名，即Name字段，值为ROW_NUMBER，
  2. 函数参数列表，即Arguments字段，值为null，即无参数
  3. Over子句，即Over字段，他的值为一个SqlOverExpression表达式，SqlOverExpression本身又包含了以下内容
    1. PartitionBy分区子句，值为一个SqlPartitionByExpression表达式，表达式的内容也非常简单，只有一个Items，即一个分区表达式的列表，在这个例子中，列表里只有一个值SqlPropertyExpression，即根据t.id分区
    2. OrderBy排序子句，值为SqlOrderByExpression表达式，表达式的内容也非常简单，只有一个Items，即一个排序表达式的列表，列表里的值为SqlOrderByItemExpression，即排序子项表达式，排序子项表达式里又包含了以下内容
      1. 排序依据，即Body字段，在这个例子中，排序依据是2个SqlPropertyExpression表达式，即根据t.NAME,t.ID排序
      2. 排序类型，即OrderByType字段，值为Asc或者Desc，默认为asc，在这2个例子中，默认排序类型都是asc
1.1.4.3 带有within group子句的函数调用
var sql = "select name,PERCENTILE_CONT(0.5) within group(order by \"number\") from TEST5 group by name";
var sqlAst = DbUtils.Parse(sql, DbType.Pgsql);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlIdentifierExpression(){Value = "name",},},new SqlSelectItemExpression(){Body = new SqlFunctionCallExpression(){Name = new SqlIdentifierExpression(){Value = "PERCENTILE_CONT",},WithinGroup = new SqlWithinGroupExpression(){OrderBy = new SqlOrderByExpression(){Items = new List<SqlOrderByItemExpression>(){new SqlOrderByItemExpression(){Body = new SqlIdentifierExpression(){Value = "number",LeftQualifiers = "\"",RightQualifiers = "\"",},},},},},Arguments = new List<SqlExpression>(){new SqlNumberExpression(){Value = 0.5M,},},},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "TEST5",},},GroupBy = new SqlGroupByExpression(){Items = new List<SqlExpression>(){new SqlIdentifierExpression(){Value = "name",},},},},
};

在这个例子中，SqlFunctionCallExpression它除了常规字段外，还包含了within group子句，具体有以下这些

  1. 函数名，即Name字段，值为PERCENTILE_CONT，
  2. 函数参数列表，即Arguments字段，列表里只有一项，表示只有1个参数，参数是SqlNumberExpression表达式，值为0.5
  3. within group子句，即WithinGroup字段，他的值为一个SqlWithinGroupExpression表达式，SqlWithinGroupExpression又包含了OrderBy排序子句，这里根据number字段排序

1.1.5 查询列为子查询的情况

var sql = "select c.*, (select a.name as province_name from portal_area a where a.id = c.province_id) as province_name, (select a.name as city_name from portal_area a where a.id = c.city_id) as city_name, (CASE WHEN c.area_id IS NULL THEN NULL ELSE (select a.name as area_name from portal_area a where a.id = c.area_id)  END )as area_name  from portal.portal_company c";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "*",},Table = new SqlIdentifierExpression(){Value = "c",},},},new SqlSelectItemExpression(){Body = new SqlSelectExpression(){Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "name",},Table = new SqlIdentifierExpression(){Value = "a",},},Alias = new SqlIdentifierExpression(){Value = "province_name",},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "portal_area",},Alias = new SqlIdentifierExpression(){Value = "a",},},Where = new SqlBinaryExpression(){Left = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "id",},Table = new SqlIdentifierExpression(){Value = "a",},},Operator = SqlBinaryOperator.EqualTo,Right = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "province_id",},Table = new SqlIdentifierExpression(){Value = "c",},},},},},Alias = new SqlIdentifierExpression(){Value = "province_name",},},new SqlSelectItemExpression(){Body = new SqlSelectExpression(){Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "name",},Table = new SqlIdentifierExpression(){Value = "a",},},Alias = new SqlIdentifierExpression(){Value = "city_name",},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "portal_area",},Alias = new SqlIdentifierExpression(){Value = "a",},},Where = new SqlBinaryExpression(){Left = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "id",},Table = new SqlIdentifierExpression(){Value = "a",},},Operator = SqlBinaryOperator.EqualTo,Right = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "city_id",},Table = new SqlIdentifierExpression(){Value = "c",},},},},},Alias = new SqlIdentifierExpression(){Value = "city_name",},},new SqlSelectItemExpression(){Body = new SqlCaseExpression(){Items = new List<SqlCaseItemExpression>(){new SqlCaseItemExpression(){Condition = new SqlBinaryExpression(){Left = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "area_id",},Table = new SqlIdentifierExpression(){Value = "c",},},Operator = SqlBinaryOperator.Is,Right = new SqlNullExpression()},Value = new SqlNullExpression()},},Else = new SqlSelectExpression(){Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "name",},Table = new SqlIdentifierExpression(){Value = "a",},},Alias = new SqlIdentifierExpression(){Value = "area_name",},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "portal_area",},Alias = new SqlIdentifierExpression(){Value = "a",},},Where = new SqlBinaryExpression(){Left = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "id",},Table = new SqlIdentifierExpression(){Value = "a",},},Operator = SqlBinaryOperator.EqualTo,Right = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "area_id",},Table = new SqlIdentifierExpression(){Value = "c",},},},},},},Alias = new SqlIdentifierExpression(){Value = "area_name",},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "portal_company",},Schema = new SqlIdentifierExpression(){Value = "portal",},Alias = new SqlIdentifierExpression(){Value = "c",},



www.51sole.com/b2b/pd_455016226.htm
www.51sole.com/b2b/pd_455016392.htm
www.51sole.com/b2b/pd_455016477.htm
www.51sole.com/b2b/pd_455016568.htm
www.51sole.com/b2b/pd_455016652.htm
www.51sole.com/b2b/pd_455016735.htm
www.51sole.com/b2b/pd_455016997.htm
www.51sole.com/b2b/pd_455017101.htm
www.51sole.com/b2b/pd_455017191.htm
www.51sole.com/b2b/pd_455017294.htm
www.51sole.com/b2b/pd_455017388.htm
www.51sole.com/b2b/pd_455017691.htm
www.51sole.com/b2b/pd_455017872.htm
www.51sole.com/b2b/pd_455017961.htm
www.51sole.com/b2b/pd_455018044.htm
www.51sole.com/b2b/pd_455018141.htm
www.51sole.com/b2b/pd_455018229.htm
www.51sole.com/b2b/pd_455019896.htm
www.51sole.com/b2b/pd_455020124.htm
www.51sole.com/b2b/pd_455020284.htm
www.51sole.com/b2b/pd_455020358.htm
www.51sole.com/b2b/pd_455020584.htm
www.51sole.com/b2b/pd_455020660.htm
www.51sole.com/b2b/pd_455020746.htm
www.51sole.com/b2b/pd_455020880.htm
www.51sole.com/b2b/pd_455020963.htm
www.51sole.com/b2b/pd_455021115.htm
www.51sole.com/b2b/pd_455021185.htm
www.51sole.com/b2b/pd_455021261.htm
www.51sole.com/b2b/pd_455021321.htm
www.51sole.com/b2b/pd_455021460.htm
www.51sole.com/b2b/pd_455021531.htm
www.51sole.com/b2b/pd_455021603.htm
www.51sole.com/b2b/pd_455021680.htm
www.51sole.com/b2b/pd_455021769.htm
www.51sole.com/b2b/pd_455021860.htm
www.51sole.com/b2b/pd_455022020.htm
www.51sole.com/b2b/pd_455022100.htm
www.51sole.com/b2b/pd_455022189.htm
www.51sole.com/b2b/pd_455022267.htm
www.51sole.com/b2b/pd_455022344.htm
www.51sole.com/b2b/pd_455022427.htm
www.51sole.com/b2b/pd_455022511.htm
www.51sole.com/b2b/pd_455022589.htm
www.51sole.com/b2b/pd_455022654.htm
www.51sole.com/b2b/pd_455022727.htm
www.51sole.com/b2b/pd_455022952.htm
www.51sole.com/b2b/pd_455023034.htm
www.51sole.com/b2b/pd_455023195.htm
www.51sole.com/b2b/pd_455023273.htm
www.51sole.com/b2b/pd_455023344.htm
www.51sole.com/b2b/pd_455023504.htm
www.51sole.com/b2b/pd_455023662.htm
www.51sole.com/b2b/pd_455023810.htm
www.51sole.com/b2b/pd_455023886.htm
www.51sole.com/b2b/pd_455023972.htm
www.51sole.com/b2b/pd_455024039.htm
www.51sole.com/b2b/pd_455025415.htm
www.51sole.com/b2b/pd_455025656.htm
www.51sole.com/b2b/pd_455025901.htm
www.51sole.com/b2b/pd_455025995.htm
www.51sole.com/b2b/pd_455026138.htm
www.51sole.com/b2b/pd_455026217.htm
www.51sole.com/b2b/pd_455026297.htm
www.51sole.com/b2b/pd_455026457.htm
www.51sole.com/b2b/pd_455026559.htm
www.51sole.com/b2b/pd_455026724.htm
www.51sole.com/b2b/pd_455026959.htm
www.51sole.com/b2b/pd_455027019.htm
www.51sole.com/b2b/pd_455027083.htm
www.51sole.com/b2b/pd_455027161.htm
www.51sole.com/b2b/pd_455027297.htm
www.51sole.com/b2b/pd_455027363.htm
www.51sole.com/b2b/pd_455027415.htm
www.51sole.com/b2b/pd_455027481.htm
www.51sole.com/b2b/pd_455027617.htm
www.51sole.com/b2b/pd_455027681.htm
www.51sole.com/b2b/pd_455027740.htm
www.51sole.com/b2b/pd_455027808.htm
www.51sole.com/b2b/pd_455027941.htm
www.51sole.com/b2b/pd_455028025.htm
www.51sole.com/b2b/pd_455028088.htm
www.51sole.com/b2b/pd_455028164.htm
www.51sole.com/b2b/pd_455028236.htm
www.51sole.com/b2b/pd_455028304.htm
www.51sole.com/b2b/pd_455028375.htm
www.51sole.com/b2b/pd_455028456.htm
www.51sole.com/b2b/pd_455028555.htm
www.51sole.com/b2b/pd_455028742.htm
www.51sole.com/b2b/pd_455028891.htm
www.51sole.com/b2b/pd_455028972.htm
www.51sole.com/b2b/pd_455029040.htm
www.51sole.com/b2b/pd_455029193.htm
www.51sole.com/b2b/pd_455029344.htm
www.51sole.com/b2b/pd_455029422.htm
www.51sole.com/b2b/pd_455029502.htm
www.51sole.com/b2b/pd_455029580.htm
www.51sole.com/b2b/pd_455031028.htm
www.51sole.com/b2b/pd_455031256.htm
www.51sole.com/b2b/pd_455031544.htm
www.51sole.com/b2b/pd_455031615.htm
www.51sole.com/b2b/pd_455031686.htm
www.51sole.com/b2b/pd_455031769.htm
www.51sole.com/b2b/pd_455031849.htm
www.51sole.com/b2b/pd_455032044.htm
www.51sole.com/b2b/pd_455032205.htm
www.51sole.com/b2b/pd_455032294.htm
www.51sole.com/b2b/pd_455032553.htm
www.51sole.com/b2b/pd_455032623.htm
www.51sole.com/b2b/pd_455032698.htm
www.51sole.com/b2b/pd_455032863.htm
www.51sole.com/b2b/pd_455032946.htm
www.51sole.com/b2b/pd_455033024.htm
www.51sole.com/b2b/pd_455033113.htm
www.51sole.com/b2b/pd_455033196.htm
www.51sole.com/b2b/pd_455033262.htm
www.51sole.com/b2b/pd_455033355.htm
www.51sole.com/b2b/pd_455033438.htm
www.51sole.com/b2b/pd_455033511.htm
www.51sole.com/b2b/pd_455033671.htm
www.51sole.com/b2b/pd_455033917.htm
www.51sole.com/b2b/pd_455033995.htm
www.51sole.com/b2b/pd_455034280.htm
www.51sole.com/b2b/pd_455034375.htm
www.51sole.com/b2b/pd_455034466.htm
www.51sole.com/b2b/pd_455034544.htm
www.51sole.com/b2b/pd_455034624.htm
www.51sole.com/b2b/pd_455034709.htm
www.51sole.com/b2b/pd_455034807.htm
www.51sole.com/b2b/pd_455034897.htm
www.51sole.com/b2b/pd_455034988.htm
www.51sole.com/b2b/pd_455035061.htm
www.51sole.com/b2b/pd_455035219.htm
www.51sole.com/b2b/pd_455035316.htm
www.51sole.com/b2b/pd_455035388.htm
www.51sole.com/b2b/pd_455035476.htm
www.51sole.com/b2b/pd_455035573.htm
www.51sole.com/b2b/pd_455037002.htm
www.51sole.com/b2b/pd_455037189.htm
www.51sole.com/b2b/pd_455037601.htm
www.51sole.com/b2b/pd_455037682.htm
www.51sole.com/b2b/pd_455037770.htm
www.51sole.com/b2b/pd_455037844.htm
www.51sole.com/b2b/pd_455037931.htm
www.51sole.com/b2b/pd_455038108.htm
www.51sole.com/b2b/pd_455038281.htm
www.51sole.com/b2b/pd_455038362.htm
www.51sole.com/b2b/pd_455038585.htm
www.51sole.com/b2b/pd_455038729.htm
www.51sole.com/b2b/pd_455038807.htm
www.51sole.com/b2b/pd_455038879.htm
www.51sole.com/b2b/pd_455038957.htm
www.51sole.com/b2b/pd_455039042.htm
www.51sole.com/b2b/pd_455039141.htm
www.51sole.com/b2b/pd_455039220.htm
www.51sole.com/b2b/pd_455039308.htm
www.51sole.com/b2b/pd_455039379.htm
www.51sole.com/b2b/pd_455039470.htm
www.51sole.com/b2b/pd_455039543.htm
www.51sole.com/b2b/pd_455039691.htm
www.51sole.com/b2b/pd_455039907.htm
www.51sole.com/b2b/pd_455039967.htm
www.51sole.com/b2b/pd_455040187.htm
www.51sole.com/b2b/pd_455040257.htm
www.51sole.com/b2b/pd_455040410.htm
www.51sole.com/b2b/pd_455040492.htm
www.51sole.com/b2b/pd_455040559.htm
www.51sole.com/b2b/pd_455040639.htm
www.51sole.com/b2b/pd_455040715.htm
www.51sole.com/b2b/pd_455040789.htm
www.51sole.com/b2b/pd_455040935.htm
www.51sole.com/b2b/pd_455041081.htm
www.51sole.com/b2b/pd_455041162.htm
www.51sole.com/b2b/pd_455041234.htm
www.51sole.com/b2b/pd_455041314.htm
www.51sole.com/b2b/pd_455041385.htm
www.51sole.com/b2b/pd_455041469.htm
www.51sole.com/xinxi/454963571.htm
www.51sole.com/xinxi/454963613.htm
www.51sole.com/xinxi/454963648.htm
www.51sole.com/xinxi/454963681.htm
www.51sole.com/xinxi/454963716.htm
www.51sole.com/xinxi/454963748.htm
www.51sole.com/xinxi/454963789.htm
www.51sole.com/xinxi/454963826.htm
www.51sole.com/xinxi/454963893.htm
www.51sole.com/xinxi/454963929.htm
www.51sole.com/xinxi/454963965.htm
www.51sole.com/xinxi/454964015.htm
www.51sole.com/xinxi/454964061.htm
www.51sole.com/xinxi/454964097.htm
www.51sole.com/xinxi/454964145.htm
www.51sole.com/xinxi/454964181.htm
www.51sole.com/xinxi/454964225.htm
www.51sole.com/xinxi/454964259.htm
www.51sole.com/xinxi/454964297.htm
www.51sole.com/xinxi/454964333.htm
www.51sole.com/xinxi/454964829.htm
www.51sole.com/xinxi/454964899.htm
www.51sole.com/xinxi/454964955.htm
www.51sole.com/xinxi/454965021.htm
www.51sole.com/xinxi/454965089.htm
www.51sole.com/xinxi/454965155.htm
www.51sole.com/xinxi/454965207.htm
www.51sole.com/xinxi/454965268.htm
www.51sole.com/xinxi/454965325.htm
www.51sole.com/xinxi/454965378.htm
www.51sole.com/xinxi/454965431.htm
www.51sole.com/xinxi/454965594.htm
www.51sole.com/xinxi/454965649.htm
www.51sole.com/xinxi/454965698.htm
www.51sole.com/xinxi/454965756.htm
www.51sole.com/xinxi/454965813.htm
www.51sole.com/xinxi/454965872.htm
www.51sole.com/xinxi/454965932.htm
www.51sole.com/xinxi/454966003.htm
www.51sole.com/xinxi/454966069.htm
www.51sole.com/xinxi/454968144.htm
www.51sole.com/xinxi/454968223.htm
www.51sole.com/xinxi/454968307.htm
www.51sole.com/xinxi/454968390.htm
www.51sole.com/xinxi/454968474.htm
www.51sole.com/xinxi/454968560.htm
www.51sole.com/xinxi/454968648.htm
www.51sole.com/xinxi/454968741.htm
www.51sole.com/xinxi/454968836.htm
www.51sole.com/xinxi/454968922.htm
www.51sole.com/xinxi/454969023.htm
www.51sole.com/xinxi/454969131.htm
www.51sole.com/xinxi/454969225.htm
www.51sole.com/xinxi/454969333.htm
www.51sole.com/xinxi/454969541.htm
www.51sole.com/xinxi/454969658.htm
www.51sole.com/xinxi/454969758.htm
www.51sole.com/xinxi/454969869.htm
www.51sole.com/xinxi/454969972.htm
www.51sole.com/xinxi/454970078.htm
www.51sole.com/xinxi/454971223.htm
www.51sole.com/xinxi/454971352.htm
www.51sole.com/xinxi/454971485.htm
www.51sole.com/xinxi/454971785.htm
www.51sole.com/xinxi/454971931.htm
www.51sole.com/xinxi/454972073.htm
www.51sole.com/xinxi/454972228.htm
www.51sole.com/xinxi/454972385.htm
www.51sole.com/xinxi/454972543.htm
www.51sole.com/xinxi/454972712.htm
www.51sole.com/xinxi/454972874.htm
www.51sole.com/xinxi/454973199.htm
www.51sole.com/xinxi/454973370.htm
www.51sole.com/xinxi/454973522.htm
www.51sole.com/xinxi/454973681.htm
www.51sole.com/xinxi/454973835.htm
www.51sole.com/xinxi/454974157.htm
www.51sole.com/xinxi/454974328.htm
www.51sole.com/xinxi/454974497.htm
www.51sole.com/xinxi/454974659.htm
www.51sole.com/xinxi/454979005.htm
www.51sole.com/xinxi/454979162.htm
www.51sole.com/xinxi/454979311.htm
www.51sole.com/xinxi/454979442.htm
www.51sole.com/xinxi/454979582.htm
www.51sole.com/xinxi/454979719.htm
www.51sole.com/xinxi/454979845.htm
www.51sole.com/xinxi/454979984.htm
www.51sole.com/xinxi/454980127.htm
www.51sole.com/xinxi/454980272.htm
www.51sole.com/xinxi/454980428.htm
www.51sole.com/xinxi/454980555.htm
www.51sole.com/xinxi/454980716.htm
www.51sole.com/xinxi/454980846.htm
www.51sole.com/xinxi/454980999.htm
www.51sole.com/xinxi/454981160.htm
www.51sole.com/xinxi/454981305.htm
www.51sole.com/xinxi/454981441.htm
www.51sole.com/xinxi/454981600.htm
www.51sole.com/xinxi/454981735.htm
www.51sole.com/xinxi/454983616.htm
www.51sole.com/xinxi/454983810.htm
www.51sole.com/xinxi/454984010.htm
www.51sole.com/xinxi/454984415.htm
www.51sole.com/xinxi/454984634.htm
www.51sole.com/xinxi/454985238.htm
www.51sole.com/xinxi/454985465.htm
www.51sole.com/xinxi/454985894.htm
www.51sole.com/xinxi/454986098.htm
www.51sole.com/xinxi/454986322.htm
www.51sole.com/xinxi/454986539.htm
www.51sole.com/xinxi/454986739.htm
www.51sole.com/xinxi/454986937.htm
www.51sole.com/xinxi/454987154.htm
www.51sole.com/xinxi/454987367.htm
www.51sole.com/xinxi/454987567.htm
www.51sole.com/xinxi/454987771.htm
www.51sole.com/xinxi/454987984.htm
www.51sole.com/xinxi/454988192.htm
www.51sole.com/xinxi/454988386.htm
www.51sole.com/xinxi/454993416.htm
www.51sole.com/xinxi/454993551.htm
www.51sole.com/xinxi/454993718.htm
www.51sole.com/xinxi/454993852.htm
www.51sole.com/xinxi/454993994.htm
www.51sole.com/xinxi/454994142.htm
www.51sole.com/xinxi/454994288.htm
www.51sole.com/xinxi/454994446.htm
www.51sole.com/xinxi/454994581.htm
www.51sole.com/xinxi/454994742.htm
www.51sole.com/xinxi/454994864.htm
www.51sole.com/xinxi/454995027.htm
www.51sole.com/xinxi/454995145.htm
www.51sole.com/xinxi/454995287.htm
www.51sole.com/xinxi/454995422.htm
www.51sole.com/xinxi/454995683.htm
www.51sole.com/xinxi/454995835.htm
www.51sole.com/xinxi/454995964.htm
www.51sole.com/xinxi/454996083.htm
www.51sole.com/xinxi/454996229.htm
www.51sole.com/xinxi/454997473.htm
www.51sole.com/xinxi/454997608.htm
www.51sole.com/xinxi/454997767.htm
www.51sole.com/xinxi/454998079.htm
www.51sole.com/xinxi/454998234.htm
www.51sole.com/xinxi/454998700.htm
www.51sole.com/xinxi/454998860.htm
www.51sole.com/xinxi/454999185.htm
www.51sole.com/xinxi/454999322.htm
www.51sole.com/xinxi/454999504.htm
www.51sole.com/xinxi/454999637.htm
www.51sole.com/xinxi/454999804.htm
www.51sole.com/xinxi/455000119.htm
www.51sole.com/xinxi/455000277.htm
www.51sole.com/xinxi/455000431.htm
www.51sole.com/xinxi/455000606.htm
www.51sole.com/xinxi/455000765.htm
www.51sole.com/xinxi/455000945.htm
www.51sole.com/xinxi/455001238.htm
www.51sole.com/xinxi/455001402.htm
www.51sole.com/xinxi/455004950.htm
www.51sole.com/xinxi/455005107.htm
www.51sole.com/xinxi/455005252.htm
www.51sole.com/xinxi/455005387.htm
www.51sole.com/xinxi/455005508.htm
www.51sole.com/xinxi/455005644.htm
www.51sole.com/xinxi/455005786.htm
www.51sole.com/xinxi/455005909.htm
www.51sole.com/xinxi/455006169.htm
www.51sole.com/xinxi/455006288.htm
www.51sole.com/xinxi/455006426.htm
www.51sole.com/xinxi/455006548.htm
www.51sole.com/xinxi/455006672.htm
www.51sole.com/xinxi/455006801.htm
www.51sole.com/xinxi/455006931.htm
www.51sole.com/xinxi/455007047.htm
www.51sole.com/xinxi/455007173.htm
www.51sole.com/xinxi/455007303.htm
www.51sole.com/xinxi/455007682.htm
www.51sole.com/xinxi/455007811.htm
www.51sole.com/xinxi/455008673.htm
www.51sole.com/xinxi/455008812.htm
www.51sole.com/xinxi/455008953.htm
www.51sole.com/xinxi/455009192.htm
www.51sole.com/xinxi/455009322.htm
www.51sole.com/xinxi/455009688.htm
www.51sole.com/xinxi/455009783.htm
www.51sole.com/xinxi/455009991.htm
www.51sole.com/xinxi/455010094.htm
www.51sole.com/xinxi/455010198.htm
www.51sole.com/xinxi/455010278.htm
www.51sole.com/xinxi/455010371.htm
www.51sole.com/xinxi/455010562.htm
www.51sole.com/xinxi/455010661.htm
www.51sole.com/xinxi/455010745.htm
www.51sole.com/xinxi/455010841.htm
www.51sole.com/xinxi/455010937.htm
www.51sole.com/xinxi/455011023.htm


},},
};

在这个例子中，要查询的列值为一个SqlSelectExpression表达式，即要查询的列是一个子查询

1.2 Where条件过滤语句

1.2.1 二元表达式

var sql = "SELECT * FROM test WHERE ID =1";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test",},},Where = new SqlBinaryExpression(){Left = new SqlIdentifierExpression(){Value = "ID",},Operator = SqlBinaryOperator.EqualTo,Right = new SqlNumberExpression(){Value = 1M,},},},
};

在这个例子中，where字段的值是一个二元表达式SqlBinaryExpression，他包含了

  1. 左边部分，即Left字段，值为一个SqlIdentifierExpression，即标识符表达式，它的值为ID
  2. 右边部分，即Right字段，值为一个SqlNumberExpression，即数字表达式，它的值为1
  3. 中间符号，即Operator字段，值为EqualTo，即等号，当然了，还可以是大于号，小于号，大于等于号，小于等于号，不等号等

二元表达式的两边可以非常灵活，可以是各种其他表达式，同时也可以自我嵌套另一个二元表达式，组成一个非常复杂的二元表达式

1.2.2 between/not between子句

var sql = "SELECT * FROM test WHERE ID BETWEEN 1 AND 2";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test",},},Where = new SqlBetweenAndExpression(){Body = new SqlIdentifierExpression(){Value = "ID",},Begin = new SqlNumberExpression(){Value = 1M,},End = new SqlNumberExpression(){Value = 2M,},},},
};

between子句包含了

  1. Begin部分，即Begin字段，在这个例子中，值为一个SqlNumberExpression，，它的值为1
  2. End部分，即End字段，在这个例子中，值为一个SqlNumberExpression，它的值为2
  3. Body主体部分，即Body字段，值为SqlIdentifierExpression，即标识符表达式，值为id
  4. 取反部分，即IsNot字段，如果是not between，则IsNot=true

1.2.3 is null/is not null子句

var sql = "select * from test rd where rd.name is null";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test",},Alias = new SqlIdentifierExpression(){Value = "rd",},},Where = new SqlBinaryExpression(){Left = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "name",},Table = new SqlIdentifierExpression(){Value = "rd",},},Operator = SqlBinaryOperator.Is,Right = new SqlNullExpression()},},
};

is null/is not null子句主要体现在二元表达式里，Operator字段为Is/IsNot，right字段为SqlNullExpression，即null表达式，代表值为null

1.2.4 exists/not exists子句

var sql = "select * from TEST t where EXISTS(select * from TEST2 t2)";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "TEST",},Alias = new SqlIdentifierExpression(){Value = "t",},},Where = new SqlExistsExpression(){Body = new SqlSelectExpression(){Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "TEST2",},Alias = new SqlIdentifierExpression(){Value = "t2",},},},},},},
};

exists/not exists子句,主要体现为SqlExistsExpression表达式，

  1. 主体，即body字段，本例子中值为一个SqlSelectExpression表达式
  2. 取反部分，即IsNot字段，如果是not exists，则IsNot=true

1.2.5 like/not like子句

var sql = "SELECT * from TEST t WHERE name LIKE '%a%'";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "TEST",},Alias = new SqlIdentifierExpression(){Value = "t",},},Where = new SqlBinaryExpression(){Left = new SqlIdentifierExpression(){Value = "name",},Operator = SqlBinaryOperator.Like,Right = new SqlStringExpression(){Value = "%a%"},},},
};

like子句,主要体现在二元表达式里，Operator字段为Like/NotLike，本例子中right字段为字符串表达式，即SqlStringExpression表达式，值为%a%。

1.2.6 all/any子句

var sql = "select * from customer c where c.Age >all(select o.Quantity  from orderdetail o)";
var sqlAst = DbUtils.Parse(sql, DbType.MySql);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "customer",},Alias = new SqlIdentifierExpression(){Value = "c",},},Where = new SqlBinaryExpression(){Left = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "Age",},Table = new SqlIdentifierExpression(){Value = "c",},},Operator = SqlBinaryOperator.GreaterThen,Right = new SqlAllExpression(){Body = new SqlSelectExpression(){Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "Quantity",},Table = new SqlIdentifierExpression(){Value = "o",},},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "orderdetail",},Alias = new SqlIdentifierExpression(){Value = "o",},},},},},},},
};

all/any子句,主要体现在SqlAllExpression/SqlAnyExpression表达式，它的body里是另一个SqlSelectExpression表达式

1.2.7 in/ not in子句

var sql = "SELECT  * from TEST t WHERE t.NAME IN ('a','b','c')";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "TEST",},Alias = new SqlIdentifierExpression(){Value = "t",},},Where = new SqlInExpression(){Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "NAME",},Table = new SqlIdentifierExpression(){Value = "t",},},TargetList = new List<SqlExpression>(){new SqlStringExpression(){Value = "a"},new SqlStringExpression(){Value = "b"},new SqlStringExpression(){Value = "c"},},},},
};

in/not in子句,主要体现在SqlInExpression表达式，它包含了

  1. body字段，即in的主体，在这里是SqlPropertyExpression，值为t.NAME
  2. TargetList字段，即in的目标列表，在这里是一个SqlExpression的列表，里面包括3个SqlStringExpression，即字符串表达式，a,b,c
  3. 取反部分，即IsNot字段，如果是not in，则IsNot=true

当然了，in也有另一种子查询的类型，即

var sql = "select * from TEST5  WHERE NAME IN (SELECT NAME  FROM TEST3)";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "TEST5",},},Where = new SqlInExpression(){Body = new SqlIdentifierExpression(){Value = "NAME",},SubQuery = new SqlSelectExpression(){Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlIdentifierExpression(){Value = "NAME",},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "TEST3",},},},},},},
};

在这里的SqlInExpression表达式中，它包含了

  1. body字段，即in的主体，在这里是SqlIdentifierExpression，值为NAME
  2. SubQuery字段，即子查询，值为一个SqlSelectExpression
  3. IsNot字段，如果是not in，则IsNot=true

1.2.8 case when子句

var sql = "SELECT CASE WHEN t.name='1' THEN 'a' WHEN t.name='2' THEN 'b' ELSE 'c' END AS v from TEST t";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlCaseExpression(){Items = new List<SqlCaseItemExpression>(){new SqlCaseItemExpression(){Condition = new SqlBinaryExpression(){Left = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "name",},Table = new SqlIdentifierExpression(){Value = "t",},},Operator = SqlBinaryOperator.EqualTo,Right = new SqlStringExpression(){Value = "1"},},Value = new SqlStringExpression(){Value = "a"},},new SqlCaseItemExpression(){Condition = new SqlBinaryExpression(){Left = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "name",},Table = new SqlIdentifierExpression(){Value = "t",},},Operator = SqlBinaryOperator.EqualTo,Right = new SqlStringExpression(){Value = "2"},},Value = new SqlStringExpression(){Value = "b"},},},Else = new SqlStringExpression(){Value = "c"},},Alias = new SqlIdentifierExpression(){Value = "v",},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "TEST",},Alias = new SqlIdentifierExpression(){Value = "t",},},},
};

case when子句,主要体现在SqlCaseExpression表达式里，他包含了

  1. 各种case when键值对的列表，即Items字段，列表里的每一个元素都是SqlCaseItemExpression表达式，SqlCaseItemExpression表达式，又包含了
    1. 条件，即Condition字段，在本例子中是二元表达式，即SqlBinaryExpression表达式，值为t.name ='1'
    2. 值，即value字段,在本例子中值为字符串a
  2. Else字段，即默认值，本例子中为字符串c

case when还有另外一种句式，如下：

var sql = "select case t.name when 'a' then 1 else 2 end  from test t ";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlCaseExpression(){Items = new List<SqlCaseItemExpression>(){new SqlCaseItemExpression(){Condition = new SqlStringExpression(){Value = "a"},Value = new SqlNumberExpression(){Value = 1M,},},},Else = new SqlNumberExpression(){Value = 2M,},Value = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "name",},Table = new SqlIdentifierExpression(){Value = "t",},},},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test",},Alias = new SqlIdentifierExpression(){Value = "t",},},},
};

在这种SqlCaseExpression表达式里，他包含了

  1. case条件的主体变量，即Value字段，本例子中值为SqlPropertyExpression，它的值为t.name
  2. 各种when then键值对的列表，即Items字段，列表里的每一个元素都是SqlCaseItemExpression表达式，SqlCaseItemExpression表达式，又包含了
    1. 条件，即Condition字段，在本例子中是字符串表达式SqlStringExpression，它的值为a
    2. 值，即Value字段,在本例子中值为SqlNumberExpression，它的值为1
  3. Else字段，即默认值，本例子中为数字2

1.2.9 not子句

var sql = "select * from TEST t WHERE not t.NAME ='abc'";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "TEST",},Alias = new SqlIdentifierExpression(){Value = "t",},},Where = new SqlNotExpression(){Body = new SqlBinaryExpression(){Left = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "NAME",},Table = new SqlIdentifierExpression(){Value = "t",},},Operator = SqlBinaryOperator.EqualTo,Right = new SqlStringExpression(){Value = "abc"},},},},
};

not子句,主要体现在SqlNotExpression表达式里，它只有一个body字段，即代表否定的部分

1.2.10 变量子句

var sql = "select * from TEST t WHERE not t.NAME =:name";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "TEST",},Alias = new SqlIdentifierExpression(){Value = "t",},},Where = new SqlNotExpression(){Body = new SqlBinaryExpression(){Left = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "NAME",},Table = new SqlIdentifierExpression(){Value = "t",},},Operator = SqlBinaryOperator.EqualTo,Right = new SqlVariableExpression(){Name = "name",Prefix = ":",},},},},
};

变量子句,主要体现在SqlVariableExpression表达式里，它包括以下部分:

  1. 变量名，即字段Name,这里值为name
  2. 变量前缀，这里值为:

1.3 From数据源

在sql中，From关键字后面有多种形式来指定数据源。主要有以下几种

1.3.1 表名或者视图

select * from test

这个解析结果上面已经演示了。

1.3.2 子查询（子表）

var sql = "select * from (select * from test) t";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlSelectExpression(){Alias = new SqlIdentifierExpression(){Value = "t",},Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test",},},},},},
};

在这个例子中，数据源From的值为一个SqlSelectExpression，即SqlSelectExpression中可以嵌套SqlSelectExpression，同时我们注意到内部的SqlSelectExpression有一个表别名的字段Alias，标识符的值为t，表示表别名为t；

1.3.3 连表查询（JOIN）

var sql = "select t1.id from test t1 left join test2 t2 on t1.id=t2.id right join test3 t3 on t2.id=t3.id";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "id",},Table = new SqlIdentifierExpression(){Value = "t1",},},},},From = new SqlJoinTableExpression(){Left = new SqlJoinTableExpression(){Left = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test",},Alias = new SqlIdentifierExpression(){Value = "t1",},},JoinType = SqlJoinType.LeftJoin,Right = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test2",},Alias = new SqlIdentifierExpression(){Value = "t2",},},Conditions = new SqlBinaryExpression(){Left = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "id",},Table = new SqlIdentifierExpression(){Value = "t1",},},Operator = SqlBinaryOperator.EqualTo,Right = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "id",},Table = new SqlIdentifierExpression(){Value = "t2",},},},},JoinType = SqlJoinType.RightJoin,Right = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test3",},Alias = new SqlIdentifierExpression(){Value = "t3",},},Conditions = new SqlBinaryExpression(){Left = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "id",},Table = new SqlIdentifierExpression(){Value = "t2",},},Operator = SqlBinaryOperator.EqualTo,Right = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "id",},Table = new SqlIdentifierExpression(){Value = "t3",},},},},},
};

在上面这个例子中，我们演示了连表查询是如何解析的，From字段的值为一个SqlJoinTableExpression，即连表查询表达式，他包含了

  1. 左边部分，即Left字段
  2. 右边部分，即Right字段
  3. 连接方式，即JoinType字段，值包括InnerJoin,LeftJoin,RightJoin,FullJoin,CrossJoin,CommaJoin
  4. 表关联条件，即Conditions字段。在这里，Conditions字段的值为一个二元表达式SqlBinaryExpression

在这个例子中，总共3张表联查，SqlJoinTableExpression中得left字段又是一个SqlJoinTableExpression，即SqlJoinTableExpression中可以嵌套SqlJoinTableExpression，无限套娃。

1.3.4 公用表表达式（CTE）

var sql = "with c1 as (select name from test t) , c2(name) AS (SELECT name FROM TEST2 t3 ) select *from c1 JOIN c2 ON c1.name=c2.name";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){WithSubQuerys = new List<SqlWithSubQueryExpression>(){new SqlWithSubQueryExpression(){Alias = new SqlIdentifierExpression(){Value = "c1",},FromSelect = new SqlSelectExpression(){Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlIdentifierExpression(){Value = "name",},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test",},Alias = new SqlIdentifierExpression(){Value = "t",},},},},},new SqlWithSubQueryExpression(){Alias = new SqlIdentifierExpression(){Value = "c2",},FromSelect = new SqlSelectExpression(){Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlIdentifierExpression(){Value = "name",},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "TEST2",},Alias = new SqlIdentifierExpression(){Value = "t3",},},},},Columns = new List<SqlIdentifierExpression>(){new SqlIdentifierExpression(){Value = "name",},},},},Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlJoinTableExpression(){Left = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "c1",},},JoinType = SqlJoinType.InnerJoin,Right = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "c2",},},Conditions = new SqlBinaryExpression(){Left = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "name",},Table = new SqlIdentifierExpression(){Value = "c1",},},Operator = SqlBinaryOperator.EqualTo,Right = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "name",},Table = new SqlIdentifierExpression(){Value = "c2",},},},},},
};

公用表表达式（CTE），主要体现在SqlSelectQueryExpression的WithSubQuerys字段，他是一个SqlWithSubQueryExpression表达式列表，即公用表列表，它里面的每一个元素都是SqlWithSubQueryExpression表达式，此表达式，包含了

  1. 公共表的来源部分，即FromSelect字段，在本例子中，他的值是一个SqlSelectExpression表达式，即一个查询
  2. 公共表的表别名，即Alias字段，在本例子中，他的值是c1
  3. 公共表的列部分，即Columns字段，在本例子中只有一个列名，即name

1.3.5 函数返回的结果集

特定数据库支持从返回结果集的函数中查询，比如oracle中添加一个自定义函数splitstr，他的作用是将一个字符串根据;号进行分割，返回多行数据

var sql = "SELECT * FROM TABLE(splitstr('a;b',';'))";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlReferenceTableExpression(){FunctionCall = new SqlFunctionCallExpression(){Name = new SqlIdentifierExpression(){Value = "TABLE",},Arguments = new List<SqlExpression>(){new SqlFunctionCallExpression(){Name = new SqlIdentifierExpression(){Value = "splitstr",},Arguments = new List<SqlExpression>(){new SqlStringExpression(){Value = "a;b"},new SqlStringExpression(){Value = ";"},},},},},}},
};

函数返回的结果集主要体现在SqlReferenceTableExpression表达式，他的内部包含了一个FunctionCall字段，值为SqlFunctionCallExpression表达式，代表从函数调用的结果集中进行查询。

1.4 OrderBy排序语句

var sql = "select fa.FlowId  from FlowActivity fa order by fa.FlowId desc,fa.Id asc";
var sqlAst = DbUtils.Parse(sql, DbType.SqlServer);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "FlowId"},Table = new SqlIdentifierExpression(){Value = "fa"},},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "FlowActivity"},Alias = new SqlIdentifierExpression(){Value = "fa"},},OrderBy = new SqlOrderByExpression(){Items = new List<SqlOrderByItemExpression>(){new SqlOrderByItemExpression(){Body =new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "FlowId"},Table = new SqlIdentifierExpression(){Value = "fa"},},OrderByType = SqlOrderByType.Desc},new SqlOrderByItemExpression(){Body =new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "Id"},Table = new SqlIdentifierExpression(){Value = "fa"},},OrderByType = SqlOrderByType.Asc},},},},
};

OrderBy排序子句，值为SqlOrderByExpression表达式，表达式的内容也非常简单，只有一个Items，即一个排序子项表达式的列表，列表里的值为SqlOrderByItemExpression，即排序子项表达式，排序子项表达式里又包含了以下内容

  1. 排序依据，即Body字段，在这个例子中，排序依据是2个SqlPropertyExpression表达式，即根据fa.FlowId,fa.Id排序
  2. 排序类型，即OrderByType字段，值为Asc或者Desc，默认为asc，在这2个例子中，有asc和Desc
  3. 决定null排在前面或后面的NullsType字段，在oracle，pgsql，sqlite中我们可以指定null在排序中的位置，如以下sql
select * from TEST5 t order by t.NAME  desc nulls FIRST,t.AGE ASC NULLS  last

那么我们的NullsType字段，他的值有SqlOrderByNullsType.First和SqlOrderByNullsType.Last,与之对应。

1.5 GroupBy分组语句

var sql = "select fa.FlowId  from FlowActivity fa group by fa.FlowId,fa.Id HAVING count(fa.Id)>1";
var sqlAst = DbUtils.Parse(sql, DbType.SqlServer);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "FlowId"},Table = new SqlIdentifierExpression(){Value = "fa"},},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "FlowActivity"},Alias = new SqlIdentifierExpression(){Value = "fa"},},GroupBy = new SqlGroupByExpression(){Items = new List<SqlExpression>(){new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "FlowId"},Table = new SqlIdentifierExpression(){Value = "fa"},},new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "Id"},Table = new SqlIdentifierExpression(){Value = "fa"},},},Having = new SqlBinaryExpression(){Left = new SqlFunctionCallExpression(){Name = new SqlIdentifierExpression(){Value = "count"},Arguments = new List<SqlExpression>(){new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "Id"},Table = new SqlIdentifierExpression(){Value = "fa"},},},},Operator = SqlBinaryOperator.GreaterThen,Right = new SqlNumberExpression(){Value = 1M},},},},
};

GroupBy分组语句，值为SqlGroupByExpression表达式，他的内容如下

  1. 分组子项表达式的列表，即Items字段，列表里的值为SqlExpression，他的值是一个逻辑子句
  2. 分组过滤子句，即Having字段，他的值是一个逻辑子句，在本例子中，逻辑子句的值为一个SqlBinaryExpression

1.5 Limit分页子句

1.5.1 mysql，sqlite

var sql = "select * from test t limit 1,5";
var sqlAst = DbUtils.Parse(sql, DbType.MySql);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test",},Alias = new SqlIdentifierExpression(){Value = "t",},},Limit = new SqlLimitExpression(){Offset = new SqlNumberExpression(){Value = 1M,},RowCount = new SqlNumberExpression(){Value = 5M,},},},
};

Limit分页子句，值为SqlLimitExpression表达式，他的内容如下

  1. 每页数量，即RowCount字段，这本例子中，值为5
  2. 跳过数量，即Offset字段,本例子中，值为1

1.5.2 oracle

var sql = "SELECT * FROM TEST3 t  ORDER BY t.NAME  DESC FETCH FIRST 2 rows ONLY";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()}},From = new SqlTableExpression(){Alias = new SqlIdentifierExpression(){Value = "t"},Name = new SqlIdentifierExpression(){Value = "TEST3"}},OrderBy = new SqlOrderByExpression(){Items = new List<SqlOrderByItemExpression>(){new SqlOrderByItemExpression(){OrderByType = SqlOrderByType.Desc,Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression() { Value = "NAME" },Table = new SqlIdentifierExpression(){Value = "t"}}}}},Limit = new SqlLimitExpression(){RowCount = new SqlNumberExpression(){Value = 2}}}
};

1.5.3 pgsql

var sql = "select * from test5   t order by t.name limit 1 offset 10;";
var sqlAst = DbUtils.Parse(sql, DbType.Pgsql);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test5",},Alias = new SqlIdentifierExpression(){Value = "t",},},OrderBy = new SqlOrderByExpression(){Items = new List<SqlOrderByItemExpression>(){new SqlOrderByItemExpression(){Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression(){Value = "name",},Table = new SqlIdentifierExpression(){Value = "t",},},},},},Limit = new SqlLimitExpression(){Offset = new SqlNumberExpression(){Value = 10M,},RowCount = new SqlNumberExpression(){Value = 1M,},},},
};

1.5.4 sqlServer

var sql = "select * from test t order by t.name OFFSET 5 ROWS FETCH NEXT 10 ROWS ONLY";
var sqlAst = DbUtils.Parse(sql, DbType.SqlServer);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()}},From = new SqlTableExpression(){Alias = new SqlIdentifierExpression(){Value = "t"},Name = new SqlIdentifierExpression(){Value = "test"}},OrderBy = new SqlOrderByExpression(){Items = new List<SqlOrderByItemExpression>(){new SqlOrderByItemExpression(){Body = new SqlPropertyExpression(){Name = new SqlIdentifierExpression() { Value = "name" },Table = new SqlIdentifierExpression(){Value = "t"}}}}},Limit = new SqlLimitExpression(){Offset = new SqlNumberExpression(){Value = 5},RowCount = new SqlNumberExpression(){Value = 10}}}
};

1.6 ConnectBy层次查询语句（oracle专用）

var sql = "SELECT EMPLOYEEID , MANAGERID , LEVEL FROM EMPLOYEE e START WITH MANAGERID IS NULL CONNECT BY NOCYCLE PRIOR EMPLOYEEID = MANAGERID ORDER SIBLINGS BY EMPLOYEEID ";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlIdentifierExpression(){Value = "EMPLOYEEID",},},new SqlSelectItemExpression(){Body = new SqlIdentifierExpression(){Value = "MANAGERID",},},new SqlSelectItemExpression(){Body = new SqlIdentifierExpression(){Value = "LEVEL",},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "EMPLOYEE",},Alias = new SqlIdentifierExpression(){Value = "e",},},ConnectBy = new SqlConnectByExpression(){StartWith = new SqlBinaryExpression(){Left = new SqlIdentifierExpression(){Value = "MANAGERID",},Operator = SqlBinaryOperator.Is,Right = new SqlNullExpression()},Body = new SqlBinaryExpression(){Left = new SqlIdentifierExpression(){Value = "EMPLOYEEID",},Operator = SqlBinaryOperator.EqualTo,Right = new SqlIdentifierExpression(){Value = "MANAGERID",},},IsNocycle = true,IsPrior = true,OrderBy = new SqlOrderByExpression(){Items = new List<SqlOrderByItemExpression>(){new SqlOrderByItemExpression(){Body = new SqlIdentifierExpression(){Value = "EMPLOYEEID",},},},IsSiblings = true,},},},
};

ConnectBy层次查询子句，值为SqlConnectByExpression表达式，他的内容如下

  1. 指定层次查询的根节点条件，即StartWith字段，本例子中他的值为SqlBinaryExpression二元表达式
  2. 主体关联条件子句，即Body字段，本例子中他的值是一个SqlBinaryExpression二元表达式
  3. IsPrior字段用来指示层次结构中哪个列是父节点，如果sql中存在Prior关键字，则值为true
  4. IsNocycle字段，用来防止循环引用导致无限递归，如果sql中存在Nocycle则为true
  5. order by子句，用于排序

1.7 Into子句(sql server专用）

var sql = "SELECT name into test14 from TEST as t ";
var sqlAst = DbUtils.Parse(sql, DbType.SqlServer);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlIdentifierExpression(){Value = "name"},},},Into = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test14"},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "TEST"},Alias = new SqlIdentifierExpression(){Value = "t"},},},
};

into子句，在本例子中值为SqlTableExpression，即into到某张表里。

2. Insert插入语句

2.1 插入单个值

var sql = "insert into test11(name,id) values('a1','a2')";
var sqlAst = DbUtils.Parse(sql, DbType.SqlServer);

解析结果如下：

var expect = new SqlInsertExpression()
{Columns = new List<SqlExpression>(){new SqlIdentifierExpression(){Value = "name"},new SqlIdentifierExpression(){Value = "id"},},ValuesList = new List<List<SqlExpression>>(){new List<SqlExpression>(){new SqlStringExpression(){Value = "a1"},new SqlStringExpression(){Value = "a2"},},},Table = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test11"},},
};

如上例子，插入语句表现为一个SqlInsertExpression，他包含了

  1. 要插入的字段列表，即Columns字段，值为一个SqlExpression的列表，本例子中值为2个SqlIdentifierExpression，它们的值为name和id，即插入name和id字段
  2. 值列表，即ValuesList字段，值为一个List<SqlExpression>的列表，即列表里的元素是一个列表，每个元素代表一组待插入的数据，本例子中列表里只有一个List，并且子列表里的值为a1和a2，即待插入的值为a1和a2。
  3. 待插入数据的表，即Table字段，本例子中值为test11

为什么ValuesList字段是列表里嵌套列表呢？主要是因为可以插入多个值列表，让我们继续往下看

2.2 插入多个值

var sql = "insert into test11(name,id) values('a1','a2'),('a3','a4')";
var sqlAst = DbUtils.Parse(sql, DbType.MySql);

解析结果如下：

var expect = new SqlInsertExpression()
{Columns = new List<SqlExpression>(){new SqlIdentifierExpression(){Value = "name"},new SqlIdentifierExpression(){Value = "id"},},ValuesList = new List<List<SqlExpression>>(){new List<SqlExpression>(){new SqlStringExpression(){Value = "a1"},new SqlStringExpression(){Value = "a2"},},new List<SqlExpression>(){new SqlStringExpression(){Value = "a3"},new SqlStringExpression(){Value = "a4"},},},Table = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test11"},},
};

在本例子中，ValuesList字段中有2个子元素，即2个List列表，代表插入2组数据，值分别为('a1','a2')和('a3','a4')

2.3 待插入的值为一个子查询

var sql = "INSERT INTO TEST2(name) SELECT name AS name2 FROM TEST t";
var sqlAst = DbUtils.Parse(sql, DbType.MySql);

解析结果如下：

var expect = new SqlInsertExpression()
{Columns = new List<SqlExpression>(){new SqlIdentifierExpression(){Value = "name"},},Table = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "TEST2"},},FromSelect = new SqlSelectExpression(){Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlIdentifierExpression(){Value = "name"},Alias = new SqlIdentifierExpression(){Value = "name2"},},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "TEST"},Alias = new SqlIdentifierExpression(){Value = "t"},},},},
};

如上例子，插入语句表现为一个SqlInsertExpression，他包含了

  1. 要插入的字段列表，即Columns字段，值为一个SqlExpression的列表，本例子中值为name
  2. 子查询来源，即FromSelect字段，值为一个SqlSelectExpression，即一个子查询
  3. 待插入数据的表，即Table字段，本例子中值为TEST2

3. Update更新语句

var sql = "update test set name ='4',d='2024-11-22 08:19:47.243' where name ='1'";
var sqlAst = DbUtils.Parse(sql, DbType.MySql);

解析结果如下：

var expect = new SqlUpdateExpression()
{Table = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test"},},Where = new SqlBinaryExpression(){Left = new SqlIdentifierExpression(){Value = "name"},Operator = SqlBinaryOperator.EqualTo,Right = new SqlStringExpression(){Value = "1"},},Items = new List<SqlExpression>(){new SqlBinaryExpression(){Left = new SqlIdentifierExpression(){Value = "name"},Operator = SqlBinaryOperator.EqualTo,Right = new SqlStringExpression(){Value = "4"},},new SqlBinaryExpression(){Left = new SqlIdentifierExpression(){Value = "d"},Operator = SqlBinaryOperator.EqualTo,Right = new SqlStringExpression(){Value = "2024-11-22 08:19:47.243"},},},
};

如上例子，更新语句表现为一个SqlUpdateExpression，他包含了

  1. 要更新的（字段-值）的列表，即Items字段，值为一个SqlExpression的列表，本例子中值为2个SqlBinaryExpression，即name='4'和d='2024-11-22 08:19:47.243'
  2. 条件过滤子句，即Where字段，代表过滤条件，本例子中值为一个SqlBinaryExpression，即name ='1'
  3. 待更新数据的表，即Table字段，本例子中值为test

4. Delete删除语句

var sql = "delete from test where name=4";
var sqlAst = DbUtils.Parse(sql, DbType.MySql);

解析结果如下：

var expect = new SqlDeleteExpression()
{Table = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test"},},Where = new SqlBinaryExpression(){Left = new SqlIdentifierExpression(){Value = "name"},Operator = SqlBinaryOperator.EqualTo,Right = new SqlNumberExpression(){Value = 4M},},
};

如上例子，删除语句表现为一个SqlDeleteExpression，他包含了

  1. 条件过滤子句，即Where字段，代表过滤条件，本例子中值为一个SqlBinaryExpression，即name=4
  2. 待删除数据的表，即Table字段，本例子中值为test

5. 注释处理

5.1 单行注释

var sql = @"select *--abc from test lbu WHERE a ='1'--aaaaaa
FROM test";
var sqlAst = DbUtils.Parse(sql, DbType.SqlServer);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test",},},},
};

如上例子，单行注释被正确忽视，解析正确。

5.2 多行注释

var sql = @"/*这是顶部*/select *--abcFROM test/*这是底部*/";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析结果如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test",},},},
};

如上例子，多行注释被正确忽视，解析正确。

6. 如何解析ast抽象语法树

当我们通过

var sql = @"select * from test";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析sql获取到抽象语法树以后，我们就要对这颗抽象语法树进行解析，获取我们想要的数据，此时就要用上访问者模式(visitor) .

6.1 访问者模式

访问者模式最大的特点就是结构与算法分离，结合本项目理解，就是ast抽象语法树这个结构已经解析出来了，你可以根据自己的需要写算法去任意解析这颗语法树。这是一个1-N的操作，即一个抽象语法树，可以对应N个解析算法，当我们要自定义算法去解析抽象语法树时，我们需要自定义一个Visitor类，并且实现IAstVisitor接口

public class CustomVisitor : IAcceptVisitor
{}

但是实现这个接口要实现接口里的很多个方法，并且有些数据并不是我们关心的，所以我提供了一个实现了IAcceptVisitor接口的抽象类BaseAstVisitor用来简化操作，我们只需要继承这个抽象类，然后重写我们感兴趣的方法即可

public class CustomVisitor : BaseAstVisitor
{}

在本项目中，我提供了2个基本的vistor供大家使用，UnitTestAstVisitor和SqlGenerationAstVisitor，大家可以参考这2个visitor去写自己的算法来解析抽象语法树。接下来，我将介绍这2个visitor的用法。

6.2 UnitTestAstVisitor

当我们通过

var sql = @"select * from test";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);

解析sql获取到抽象语法树之后，sqlAst其实还是一个数据结构，我们可以通过vs监视这个变量来查看内部的结构，但是如果是非常复杂的sql，那这颗树会巨大无比，要靠我们手动去慢慢点开查看得累死，没错！写单元测试的时候，我刚开始都是用手写的结果去对比引擎解析出来的结果，后来我就被累死了，该说不说，这活真不是人干的，所以痛定思痛之后我就写了这个UnitTestAstVisitor来替我生成ast的结构字符串，接下来让我们看看用法

var sql = @"select * from test";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);
var unitTestAstVisitor = new UnitTestAstVisitor();
sqlAst.Accept(unitTestAstVisitor);
var result = unitTestAstVisitor.GetResult();

其中的result就是解析抽象语法树生成的字符串，如下：

var expect = new SqlSelectExpression()
{Query = new SqlSelectQueryExpression(){Columns = new List<SqlSelectItemExpression>(){new SqlSelectItemExpression(){Body = new SqlAllColumnExpression()},},From = new SqlTableExpression(){Name = new SqlIdentifierExpression(){Value = "test",},},},
};

然后把这个生成的字符串黏贴到vs里去和引擎生成的结果进行对比，

Assert.True(sqlAst.Equals(expect));

至此，我写单元测试的工作量大大减轻，同时对于生成的sqlAst语法树的结构也更加一目了然了。

6.2 SqlGenerationAstVisitor

我们通过解析sql生成了抽象语法树之后，如果我们想要给这颗抽象语法树添加一个where条件,比如添加test.name ='a'

var sql = @"select * from test";
var sqlAst = DbUtils.Parse(sql, DbType.Oracle);
if (sqlAst is SqlSelectExpression sqlSelectExpression && sqlSelectExpression.Query is SqlSelectQueryExpression sqlSelectQueryExpression)
{sqlSelectQueryExpression.Where = new SqlBinaryExpression(){Left = new SqlPropertyExpression(){Table = new SqlIdentifierExpression(){Value = "test"},Name = new SqlIdentifierExpression(){Value = "name"}},Operator = SqlBinaryOperator.EqualTo,Right = new SqlStringExpression(){Value = "a"}};
}

好了，现在我们添加完了，接下来我们肯定是想着把抽象语法树转化为sql语句，此时，就需要用上SqlGenerationAstVisitor了，他就是负责把抽象语法树转化为sql的

var sqlGenerationAstVisitor = new SqlGenerationAstVisitor(DbType.Oracle);
sqlAst.Accept(sqlGenerationAstVisitor);
var newSql = sqlGenerationAstVisitor.GetResult();

我们获取到的newSql就是新的sql了，他的值为

select * from test where(test.name = 'a')

至此，我们的目的就达到了。

7. sql解析的理论基础

sql之所以能被我们解析出来，主要是因为sql是一种形式语言，自然语言和形式语言的一个重要区别是，自然语言的一个语句，可能有多重含义，而形式语言的一个语句，只能有一个语义;形式语言的语法是人为规定的，有了一定的语法规则，语法解析器就能根据语法规则，解析出一个语句的唯一含义。

项目感悟

  1. 解决嵌套问题的唯一方案，就是用递归
  2. 对于基础项目，单元测试非常非常重要，因为开发的过程中可能会不断地重构，那以前跑过的测试案例就有可能失败，如果此时需要靠人手工去回归测试验证的话，那工作量是天量的，做不完，根本做不完，所以正确的解决方案是写单元测试，新添加一个功能后，为这个功能写1-N个单元测试，确保新功能对各种情况都有覆盖到，然后再跑一遍所有单元测试，确保没有影响到旧的功能。当然了，跑单元测试最让我崩溃的是，跑一遍所有单元测试，红了（即失败）几十个，天都塌了。

开源地址，欢迎star

本项目基于MIT协议开源，地址为
https://github.com/TripleView/SqlParser.Net

同时感谢以下项目

  1. 阿里巴巴开源的druid

写在最后

如果各位靓仔觉得这个项目不错，欢迎一键三连（推荐，star，关注）,同时欢迎加入三合的开源交流群，QQ群号：799648362

QQ群799648362

 
分类: net core

本文来自互联网用户投稿，该文观点仅代表作者本人，不代表本站立场。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如若转载，请注明出处：http://www.hqwc.cn/news/898482.html

如若内容造成侵权/违法违规/事实不符，请联系编程知识网进行投诉反馈email:809451989@qq.com，一经查实，立即删除！

相关文章

为了改一行代码，我花了10多天时间，让性能提升了40多倍---Pascal架构GPU在vllm下的模型推理优化 ChatGPT生成的文章摘要

为了改一行代码，我花了10多天时间，让性能提升了40多倍---Pascal架构GPU在vllm下的模型推理优化 ChatGPT生成的文章摘要

ChatGPT生成的文章摘要 这篇博客记录了作者在家中使用Pascal显卡运行大型模型时遇到的挑战和解决方案。随着本地大型模型性能的提升，作者选择使用vllm库进行推理。然而，作者遇到了多个技术难题，需要自行编译vllm和PyTorch，以支持Pascal架构的显卡。编译过程中，作者深入研究…
阅读更多...
从 CephFS 到 JuiceFS：同程旅行亿级文件存储平台构建之路

从 CephFS 到 JuiceFS：同程旅行亿级文件存储平台构建之路

随着公司业务的快速发展，同程旅行的非结构化的数据突破 10 亿，在 2022 年，同程首先完成了对象存储服务的建设。当时，分布式文件系统方面，同程使用的是 CephFS，随着数据量的持续增长，CephFS 的高复杂性和运维难度逐渐成为瓶颈。考虑到可观测性、稳定性和管理效率等维度，…
阅读更多...
ChatGPT在功能测试红胖子(红模仿)用例生成方面的优势

ChatGPT在功能测试红胖子(红模仿)用例生成方面的优势

前言在OSG中，对于一些效果未被选中或者包含等业务，需要半透明效果来实现。  本篇描述OSG的半透明实现方式。 Demo 透明功能概述透明效果在三维场景中扮演着重要角色，它能够模拟玻璃、水体、烟雾等自然现象，增加场景的层次感和真实感。然而，透明效果的实现并非易事，它涉…
阅读更多...
vue3 axios

vue3 axios

默认情况下，vue中并没有对ajax进行封装的，所以我们需要下载安装第三方httpajax工具包---axios。 官方文档：https://axios-http.com/zh/docs/intro在项目**根目录**下打开终端，使用 npm或者yarn安装包# npm install axios yarn add axios 接着在src目录下创建一个utils/http…
阅读更多...
vue3 项目编译打包

vue3 项目编译打包

打包编译 不管我们使用的是vue-cli还是vite进行项目构建和管理，将来要进行项目的部署迁移到外网服务器时，都是需要使用打包后的项目代码，打包后的代码会进行压缩，并且只需要运行在http服务器下面即可。我们一般在公司里面往往使用nginx来运行打包后的web前端项目。# vite的…
阅读更多...
SpringBoot3集成Mybatis

SpringBoot3集成Mybatis

Mybatis Mybatis是一款优秀的持久层框架，支持自定义SQL，Mybatis可以通过简单的XML或注解来配置和映射原始类型、接口和Java对象为数据库中的记录 SpringBoot配置Mybatis 前提pom.xml中已经导入mybatis依赖<dependency><groupId>org.mybatis.spring.boot</grou…
阅读更多...
搜维尔科技：灵巧手和手套，直观的控制尽在您的手掌之中

搜维尔科技：灵巧手和手套，直观的控制尽在您的手掌之中

轻质手套可模仿您的动作，实现终极控制 我们将灵巧手与轻量级的影子手套相结合，为机器人操控和抓取创造了一种新的控制和自动化解决方案。机器人手结合了直观的控制和无与伦比的运动自由度，可以准确模仿您的动作，精确地完成复杂的任务。 用途和好处 1.最小的延迟让您轻松实现…
阅读更多...
【硬件测试】基于FPGA的MSK调制解调系统系统开发与硬件片内测试,包含信道模块,误码统计模块,可设置SNR

【硬件测试】基于FPGA的MSK调制解调系统系统开发与硬件片内测试,包含信道模块,误码统计模块,可设置SNR

1.算法仿真效果 本文是之前写的文章:《基于FPGA的MSK调制解调系统verilog开发,包含testbench,同步模块,高斯信道模拟模块,误码率统计模块》的硬件测试版本。在系统在仿真版本基础上增加了ila在线数据采集模块，vio在线SNR设置模块，数据源模块。硬件ila测试结果如下：（完整代码…
阅读更多...
根据空域图信息构造飞机航线图以及飞行轨迹模拟matlab仿真

根据空域图信息构造飞机航线图以及飞行轨迹模拟matlab仿真

1.程序功能描述 空域图是指航空领域中的一种图形表示方式，它涵盖了空中交通管理所需要的各种信息，比如航线、导航点、飞行高度层、飞行限制等。空域图是航空人员进行飞行计划制定的重要工具。在本课题中，根据空域图信息构造飞机航线图以及飞行轨迹模拟matlab仿真。 2.…
阅读更多...
基于MobileNet深度学习网络的活体人脸识别检测算法matlab仿真

基于MobileNet深度学习网络的活体人脸识别检测算法matlab仿真

1.算法运行效果图预览 (完整程序运行后无水印) 2.算法运行软件版本 matlab2022a3.部分核心程序 （完整版代码包含详细中文注释和操作步骤视频）classs = 2; % 创建一个图像数据存储对象imdsTrain，用于从名为"Data"的文件夹及其子文件夹中读取图像数据。 % "…
阅读更多...
2021年-PTA模拟赛-L1-8 编程团体赛(仅代码)

2021年-PTA模拟赛-L1-8 编程团体赛(仅代码)

简单题，无解析没必要存进去再遍历数组，数组就起一个记忆的作用，我还没想到有什么优化的办法。AcCode: #include<bits/stdc++.h> using namespace std; int team[10010]; int main(){int winner = 0, max = 0, N;cin >> N;while(N--){int tid, id, g;scanf("…
阅读更多...
[AI/GPT/综述] AI Agent的设计模式综述

[AI/GPT/综述] AI Agent的设计模式综述

【AI Agent】作为【AI应用层】的三大件(Prompt/RAG/Agent[MCP])之一， AI Agent的设计模式，作为未来或正在向AI开发转型的IT从业人员(开发人员/产品经理等)，不得不深入研究研究。序：文由其一，随着大模型的发展，通用智能不断迭代升级，应用模式也不断创新，从简单的Prompt应…
阅读更多...
推荐文章
最新文章

Copyright @ 2022~2023