Access 中case when then else end不支持使用switch代替

这里主要是实现一个表中多个字段，多个字段之间作比较然后取得最大值或者最小值用来处理

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>

但是发现在access中不好使

接下来使用access支持的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
查询结果截图如下：
 <img src="http://img.blog.csdn.net/20150312110307552?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvY2hlbmhvbmd3dTY2Ng==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" /></span>

在此记录一下，哈哈