zoukankan      html  css  js  c++  java
  • 一个比较复杂的查询语句

     Access中不支持视图,认为视图是个复杂查询。

    Create View TV as
    select B.IPDCode as 类别,B.Grade,count(B.Grade) as 数目 From WW_IPD A,WW_SM B Where A.IPDCode = B.IPDCode And B.Grade="建议推荐"  group by B.IPDCode,B.Grade
    union
    select B.IPDCode as 类别,B.Grade,count(B.Grade) as 数目 From WW_IPD A,WW_SM B Where A.IPDCode = B.IPDCode And B.Grade="暂不推荐" group by B.IPDCode,B.Grade;

    Access中不认识关键字“View”。

    第一版查询语句:

    select B.IPDCode as 类别,B.Grade,count(B.Grade) as 数目 From WW_IPD A,WW_SM B Where A.IPDCode = B.IPDCode And B.Grade="建议推荐"  group by B.IPDCode,B.Grade
    union
    select B.IPDCode as 类别,B.Grade,count(B.Grade) as 数目 From WW_IPD A,WW_SM B Where A.IPDCode = B.IPDCode And B.Grade="暂不推荐" group by B.IPDCode,B.Grade;

    第二版改进型查询语句:

     select B.IPDCode as 类别,count(B.Grade) as 建议推荐,

    (select count(B.Grade) From WW_IPD C,WW_SM D Where C.IPDCode = D.IPDCode And D.Grade="暂不推荐" AND C.IPDCode=B.IPDCode )as 暂不推荐

    From WW_IPD A,WW_SM B Where A.IPDCode = B.IPDCode And B.Grade="建议推荐"  group by B.IPDCode,B.Grade

    第二版语句有漏洞,下面为第三版改进型查询语句:

    select B.IPDCode as 类别,
    (select count(B.Grade) From WW_IPD C,WW_SM D Where C.IPDCode = D.IPDCode And D.Grade="暂不推荐" AND C.IPDCode=B.IPDCode )as 暂不推荐, count(B.Grade) as 建议推荐

    From WW_IPD A,WW_SM B Where A.IPDCode = B.IPDCode And B.Grade="建议推荐"  group by B.IPDCode,B.Grade

    union
    select B.IPDCode as 类别,count(B.Grade) as 暂不推荐,

    (select count(B.Grade) From WW_IPD C,WW_SM D Where C.IPDCode = D.IPDCode And D.Grade="建议推荐" AND C.IPDCode=B.IPDCode )as 建议推荐

    From WW_IPD A,WW_SM B Where A.IPDCode = B.IPDCode And B.Grade="暂不推荐"  group by B.IPDCode,B.Grade

    *感悟:用户需求促使我们技术探索!

  • 相关阅读:
    C# 图像处理(图像缩放、屏幕截取、图像合并、保存图像)
    C# string ASCII相互转换
    BitNami Redmine Stack迁移
    win10开始菜单打不开怎么办?
    (.text+0x18): undefined reference to `main'
    CUDA 计算pi (π)
    C++ 对TXT 的串并行读写
    Matlab 与 c++对txt 文档的读写格式
    Git 初级使用 windows & Ubuntu
    Leetcode 题解 Remove Duplicates from Sorted List
  • 原文地址:https://www.cnblogs.com/wuhenke/p/1776562.html
Copyright © 2011-2022 走看看