数据库sql游标和递归实例讲解与分析

DECLARE @UserID INT; --推广员帐号
DECLARE @ProxyID INT; --代理帐号
DECLARE @Score INT=1000; --分数
SELECT
    @UserID = [SpreaderID]
FROM
    [QPAccountsDB].[dbo].[AccountsInfo]
WHERE
    UserID = 5055;
SELECT --查出推广员的代理帐号
        @ProxyID = ProxyID
FROM
        [QPAccountsDB].[dbo].[AccountsInfo]
    LEFT JOIN
        [QPProxyDB].[dbo].[BS_ProxyInfo]
            ON BS_ProxyInfo.account = AccountsInfo.Accounts
WHERE
        UserID = @UserID;
PRINT @ProxyID;
CREATE TABLE #ProxyInfo
    (
        belongsAgent     INT,
        assignProportion TINYINT
    );
WITH cte
AS (   SELECT
           belongsAgent
       FROM
           [QPProxyDB].[dbo].[BS_ProxyInfo]
       WHERE
           ProxyID = @ProxyID
           AND belongsAgent <> -1
       UNION ALL
       SELECT
               a.belongsAgent
       FROM
               [QPProxyDB].[dbo].[BS_ProxyInfo] a
           JOIN
               cte                              b
                   ON a.ProxyID = b.belongsAgent
       WHERE
               a.belongsAgent <> -1)
INSERT #ProxyInfo
    (
        belongsAgent,
        assignProportion
    )
       SELECT
           BS_ProxyInfo.ProxyID,
           assignProportion
       FROM
           cte LEFT JOIN [QPProxyDB].[dbo].[BS_ProxyInfo] ON BS_ProxyInfo.ProxyID = cte.belongsAgent
       ORDER BY
           BS_ProxyInfo.belongsAgent ASC;
---游标更新删除当前数据
---1.声明游标
DECLARE cursor01 CURSOR SCROLL FOR
    SELECT
        *
    FROM
        #ProxyInfo
    ORDER BY
        belongsAgent ASC;
        DECLARE @AllTax INT 
        SET @AllTax =@Score
--2.打开游标
OPEN cursor01;
--3.声明游标提取数据所要存放的变量
DECLARE
    @belongsAgent     INT,
    @assignProportion TINYINT;
--4.定位游标到哪一行
FETCH FIRST FROM cursor01
INTO
    @belongsAgent,
    @assignProportion; --into的变量数量必须与游标查询结果集的列数相同
WHILE @@fetch_status = 0 --提取成功，进行下一条数据的提取操作 
    BEGIN

      SET   @AllTax=@assignProportion*@AllTax/100
UPDATE [QPProxyDB].[dbo].[BS_ProxyInfo] SET allTax+=@AllTax WHERE ProxyID=@belongsAgent
        FETCH NEXT FROM cursor01
        INTO
            @belongsAgent,
            @assignProportion; --移动游标
    END;
CLOSE cursor01;
DEALLOCATE cursor01;
DROP TABLE #ProxyInfo;