mysql - 选择删除分类最多的用户以及分类的数量

Question

从如下表中，我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"

我对基本的 sql 语句没问题，但看不到找到一种方法来做到这一点。

select max(count(classStatus)) as t, userid as u from testtops where classStatus=6;

Answer 1

这将选择至少有一个已删除类字段的所有用户，并将显示所有类字段的数量和所有已删除的类字段的数量：

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：这是一种使用连接的替代方法，它看起来不像其他查询那么优雅，但它确实更快：

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

EDIT2：无论如何，如果您正在寻找已删除类字段的最大数量，那么您可以使用它：

select max(numberofDeletedClassfields)
from (
  select count(*) as numberofDeletedClassfields
  from your_table
  where classStatus = 6
  group by userid) s

Answer 2

你缺乏GROUP BY你的查询，

SELECT userid, COUNT(*) NumberOfClassified
FROM tableName
WHERE classStatus = 6
GROUP BY userID
ORDER BY NumberOfClassified DESC

• SQLFiddle 演示链接

Answer 3

select count(*) as numberofClassifieds, userid from testtops
where classStatus=6
group by userid

试试这个

Answer 4

SELECT userid, COUNT(*) NumberOfClassified
FROM tableName WHERE classStatus = 6 
GROUP BY  userID 
ORDER BY NumberOfClassified DESC limit 1

Answer 5

请尝试下面给出的查询

SELECT `userid` , count(*) AS numberofClassifieds   FROM `testtops` where  `classStatus` = 6 group by `userid`  order by numberofClassifieds DESC

谢谢