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sql server 函数参数表(SQL Server 实现数字辅助表实例代码)

更多 时间:2022-03-28 22:36:49 类别:数据库 浏览量:1001

sql server 函数参数表

SQL Server 实现数字辅助表实例代码

数字辅助表是一个连续整数的数列,通常用来实现多种不同的查询任务。大多分两类:足够大物理数字表和表函数,前者可以称为静态的,后者可以称为动态且按需生产。

物理数字表

    物理数字表通常存在一个物理表,表记录相对足够大,相关的T-SQL代码如下:

  • IF OBJECT_ID(N'dbo.Nums', 'U') IS NOT NULL
    BEGIN
      DROP TABLE dbo.Nums;
    END
    GO
     
    CREATE TABLE dbo.Nums 
    (
      Num INT NOT NULL,
      CONSTRAINT PK_U_CL_Nums_Num PRIMARY KEY CLUSTERED
      (
        Num ASC
      ) 
    );
    GO
     
    INSERT INTO dbo.Nums (Num)
    SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS RowNum
    FROM master.dbo.spt_values;
    GO
    
  • 注意:如何填充物理数字表的方法很多,为了演示作用使用了一种。

    测试的T-SQL代码如下:

  • 1 SELECT Num
    2 FROM dbo.Nums;
    3 GO
    
  • 执行后的查询结果如下:

    sql server 函数参数表(SQL Server 实现数字辅助表实例代码)

     表函数

        表函数实现使用交叉连接和CTE,SQL Server 2005和以上版本的T-SQL代码如下:

  • IF OBJECT_ID(N'dbo.ufn_GetNums', N'IF') IS NOT NULL
    BEGIN
      DROP TABLE dbo.ufn_GetNums;
    END
    GO
     
    --==================================
    -- 功能: 获取指定范围的数字数列
    -- 说明: 交叉最后层级的CTE得到的数据行:在L级(从0开始计数)得到的行的总数为2^2^L。
    --    例如:在5级就会得到4 294 967 596行。5级的CTE提供了超过40亿的行。
    -- 作者: XXX
    -- 创建: yyyy-MM-dd
    -- 修改: yyyy-MM-dd XXX 修改内容描述
    --==================================
    CREATE FUNCTION dbo.ufn_GetNums
    (
      @bintLow BIGINT,
      @bintHigh BIGINT
    ) RETURNS TABLE
    AS
    RETURN 
      WITH
        L0 AS (SELECT c FROM (VALUES(1), (1)) AS LO(c)),
        L1 AS (SELECT 1 AS c FROM L0 AS T CROSS JOIN L0 AS T2),
        L2 AS (SELECT 1 AS c FROM L1 AS T CROSS JOIN L1 AS T2),
        L3 AS (SELECT 1 AS c FROM L2 AS T CROSS JOIN L2 AS T2),
        L4 AS (SELECT 1 AS c FROM L3 AS T CROSS JOIN L3 AS T2),
        L5 AS (SELECT 1 AS c FROM L4 AS T CROSS JOIN L4 AS T2),
        Nums AS (SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS RowNum FROM L5)
     
      SELECT TOP (@bintHigh - @bintLow + 1) @bintLow + RowNum - 1 AS Num
      FROM Nums
      ORDER BY RowNum ASC;
    GO
    
  •     SQL Server 2012增加了有关分页的新特性,相关的T-SQL代码如下:

  • IF OBJECT_ID(N'dbo.ufn_GetNums2', N'IF') IS NOT NULL
    BEGIN
      DROP TABLE dbo.ufn_GetNums2;
    END
    GO
     
    --==================================
    -- 功能: 获取指定范围的数字数列
    -- 说明: 交叉最后层级的CTE得到的数据行:在L级(从0开始计数)得到的行的总数为2^2^L。
    --    例如:在5级就会得到4 294 967 596行。5级的CTE提供了超过40亿的行。 
    -- 作者: XXX
    -- 创建: yyyy-MM-dd
    -- 修改: yyyy-MM-dd XXX 修改内容描述
    --==================================
    CREATE FUNCTION dbo.ufn_GetNums2
    (
      @bintLow BIGINT,
      @bintHigh BIGINT
    ) RETURNS TABLE
    AS
    RETURN 
      WITH
        L0 AS (SELECT c FROM (VALUES(1), (1)) AS LO(c)),
        L1 AS (SELECT 1 AS c FROM L0 AS T CROSS JOIN L0 AS T2),
        L2 AS (SELECT 1 AS c FROM L1 AS T CROSS JOIN L1 AS T2),
        L3 AS (SELECT 1 AS c FROM L2 AS T CROSS JOIN L2 AS T2),
        L4 AS (SELECT 1 AS c FROM L3 AS T CROSS JOIN L3 AS T2),
        L5 AS (SELECT 1 AS c FROM L4 AS T CROSS JOIN L4 AS T2),
        Nums AS (SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS RowNum FROM L5)
     
      SELECT @bintLow + RowNum - 1 AS Num
      FROM Nums
      ORDER BY RowNum ASC
      OFFSET 0 ROWS FETCH FIRST @bintHigh - @bintLow + 1 ROWS ONLY;
    GO
    
  • 以函数ufn_GetNums为例,演示相关的效果。获取指定范围的数字序列的T-SQL代码如下:

  • SELECT Num
    FROM dbo.ufn_GetNums(11, 20);
    GO
    
    
  • 执行后的查询结果如下:

    sql server 函数参数表(SQL Server 实现数字辅助表实例代码)
     

    博友如有其他更好的解决方案,也请不吝赐教,万分感谢。

    参考清单列表

    1、《Microsoft SQL Server 2012 High-Performance T-SQL Using Window Functions》 作者 Itzik Ben-Gan(美国)(SQL Server Inside 有关书籍的作者)

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