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这两天项目里出了一个问题，LIMIT使用后报错。
需求是这样的，我有3张表，infor信息表，mconfig物料配置表，maaply物料申请表，要求是读出申请表中哪些人申请哪些物料
于是我先是这样写的：
SELECT infor.name,infor.phone,infor.add,
mconfig.mname,mapply.acount,from_unixtime(mapply.atime,'%Y-%m-%d') as 'atime'
FROM mapply right JOIN infor ON mapply.uid = infor.uid inner JOIN mconfig ON mapply.mid = mconfig.mid
WHERE mapply.aid
IN (
SELECT aid
FROM `mapply` where state = $state
ORDER BY `atime` , `uid` DESC
LIMIT 0,10
)
结果报错了
当时没注意报的什么错误，只是看到LIMIT什么的错误，于是改了下代码
SELECT infor.name,infor.phone,infor.add,
mconfig.mname,mapply.acount,from_unixtime(mapply.atime,'%Y-%m-%d') as 'atime'
FROM mapply right JOIN infor ON mapply.uid = infor.uid inner JOIN mconfig ON mapply.mid = mconfig.mid
WHERE mapply.aid
IN (
SELECT aid
FROM `mapply` where state = $state
ORDER BY `atime` , `uid` DESC
)
LIMIT 0,10
这样没有报错，莫离以为OK了，但是运行后发现，数据有问题
和单纯的读出申请表的内容不一样，才发现LIMIT的位置放错了，于是又把LIMIT发在IN里，结果报错如下
This version of MySQL doesn't yet support ‘LIMIT & IN/ALL/ANY/SOME subquery'
细看才知道，IN里不支持LIMIT。那怎么办呢？
于是度娘后得知，在IN里再使用一张临时表，把需要的内容先查出来，
修改后代码如下：
SELECT infor.name,infor.phone,infor.add,
mconfig.mname,mapply.acount,from_unixtime(mapply.atime,'%Y-%m-%d') as 'atime'
FROM mapply right JOIN infor ON mapply.uid = infor.uid inner JOIN mconfig ON mapply.mid = mconfig.mid
WHERE mapply.aid
IN (
SELECT aid
FROM （SELECT `aid` FROM `mapply` where state = $state
ORDER BY `atime` , `uid` DESC
LIMIT 0,10）AS `tp`
)
运行后，问题解决~~~bitsCN.com
