从如下表中,如何选择删除分类广告最多的用户以及删除分类广告的数量?在这里:6 = 已删除。我正在使用 mySql。
"userid" "classStatus"
"1" "6"
"1" "6"
"2" "0"
"2" "6"
"3" "0"
"3" "0"
所以在这种情况下,输出将是:
"userid" "numberofClassifieds"
"1" "2"
"2" "1"
我可以使用基本的 sql 语句,但找不到方法来做到这一点。
select max(count(classStatus)) as t, userid as u from testtops where classStatus=6;
最佳答案
这将选择至少有一个已删除类字段的所有用户,并显示所有类字段的数量和所有已删除类字段的数量:
SELECT
userid,
count(*) as numberofClassifieds,
sum(classStatus=6) as numberofDeletedClassfields
FROM
your_table
GROUP BY userid
HAVING numberofDeletedClassfields>0
ORDER BY numberofDeletedClassfields DESC
编辑:这是使用联接的替代方案,它看起来不像其他查询那么优雅,但它肯定更快:
SELECT dc.userid, c.numberofClassfields, dc.numberofDeletedClassfields
FROM
(select userid, count(*) as numberofDeletedClassfields
from your_table
where classStatus = 6
group by userid
having count(*)>0) dc
INNER JOIN
(select userid, count(*) as numberofClassfields
from your_table
group by userid) c
on dc.userid=c.userid
ORDER BY dc.numberofDeletedClassfields desc
编辑2:无论如何,如果您正在寻找删除的类字段的最大数量,那么您可以使用以下方法:
select max(numberofDeletedClassfields)
from (
select count(*) as numberofDeletedClassfields
from your_table
where classStatus = 6
group by userid) s
关于mysql - 选择删除分类广告最多的用户以及分类广告数量,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/14039915/