Access 中case when then else end不支援使用switch代替，caseswitch

Access 中case when then else end不支援使用switch代替，caseswitch

Access 中case when then else end不支援使用switch代替

這裡主要是實現一個表中多個欄位，多個欄位之間作比較然後取得最大值或者最小值用來處理

case when then else end 例子

<span style="font-family:Microsoft YaHei;font-size:14px;">selece f1,f2,(case when f1>f2 then f1 else f2 end) as a from table</span>

但是發現在access中不好使

接下來使用access支援的switch代替如下

<span style="font-family:Microsoft YaHei;font-size:14px;">select * from(    select topvalue,bottomvalue,leftvalue,rightvalue,    switch    (        a > b,a,        a <= b,b    ) as result    from    (        select topvalue,bottomvalue,leftvalue,rightvalue,        switch        (            topvalue > bottomvalue,topvalue,            topvalue <= bottomvalue,bottomvalue        ) as a,        switch        (            leftvalue > rightvalue,leftvalue,            leftvalue <= rightvalue,rightvalue        ) as b        from imagehandle    ))order by result desc查詢結果如下： <img src="http://img.blog.csdn.net/20150312110307552?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvY2hlbmhvbmd3dTY2Ng==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" /></span>

在此記錄一下，哈哈