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  • SQL嵌套查询总结 潇湘博客

           IT也有一段时间了,刚开始的时候``````

    的困难主要是在编程语言上,数组,逻辑,算法,...

    这些都过来了之后,困难就上升到数据库设计上了.

    以及数据逻辑.

    一个优秀的系统,会集成优秀的程序和优秀的数据库设计.

    要做到这点得有足够的经验.

    这是我写的一个结合UINON的嵌套查询.

    将五个方面的报表放到一个临时表里,再从临时表里,将

    所要的数据查询出来.

    $sql="SELECT type , sum( yjsl ) as yjsl , sum( yysl ) as yysl, sum( jyrs ) as jyrs, sum( jycs ) as jycs
    FROM (

    SELECT c.mc AS
    TYPE , count( d.lsh ) AS yjsl, 0 AS yysl, 0 AS jyrs, 0 AS jycs
    FROM sys_dzxxb AS b, sys_jcb AS c, sys_dzyjb AS d
    WHERE b.bm = c.lsh
    AND d.dzlsh = b.lsh
    GROUP BY c.mc
    UNION SELECT c.mc AS
    TYPE , 0 AS yjsl, count( e.lsh ) AS yysl, 0 AS jyrs, 0 AS jycs
    FROM sys_dzxxb AS b, sys_jcb AS c, sys_dzyy AS e
    WHERE b.bm = c.lsh
    AND e.dzlsh = b.lsh
    GROUP BY c.mc
    UNION SELECT c.mc AS
    TYPE , 0 AS yjsl, 0 AS yysl, count( DISTINCT e.dzlsh ) AS jyrs, 0 AS jycs
    FROM sys_dzxxb AS b, sys_jcb AS c, sys_ltxxb AS e
    WHERE b.bm = c.lsh
    AND e.dzlsh = b.lsh
    GROUP BY c.mc
    UNION SELECT c.mc AS
    TYPE , 0 AS yjsl, 0 AS yysl, 0 AS jyrs, count( DISTINCT e.lsh ) AS jycs
    FROM sys_dzxxb AS b, sys_jcb AS c, sys_ltxxb AS e
    WHERE b.bm = c.lsh
    AND e.dzlsh = b.lsh
    GROUP BY c.mc
    ) AS temptable
    GROUP BY TYPE ";

    分享给大家.

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  • 原文地址:https://www.cnblogs.com/fengju/p/6174011.html
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