Question

从下面的表格中，如何选择删除分类最多的用户以及已删除分类的数量？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，但看不到找到办法。

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的类字段的所有用户，它将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：这是一种使用连接的替代方案，它看起来不像其他查询那么优雅，但它的速度要快得多：

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的Classfields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

您的查询中缺少GROUP BY，

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

SQLFiddle Demo Link

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

请尝试下面的查询

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

感谢

选择包含最多已删除分类的用户以及分类的数量

5 个答案: