Question

数据库：SQL Server 2008

如果该用户ID在两个表中多次出现，我想从表中选择id, title和userid。

因此，如果用户在位置表中有2条记录，在艺术家表中有1条记录，那么我想返回所有3条记录的id，title和userid。

这就是我现在所拥有的，但它会返回0条记录。

当我省略“有计数（用户ID）＆gt; 1”部分时，我会在所有表格中获得所有400条记录。

select userid,id,title from (
select id,title,userid from locations l
union
select id,title,userid from artists a
) as info
group by userid,id,title
having count(userid)>1

Answer 1

这样的事情应该有效：

select userid,id,title 
from 
( select id,title,userid from locations l union select id,title,userid from artists a )
as grabfromthis
where userid in (
select userid
( select id,title,userid from locations l union select id,title,userid from artists a )
as info 
group by userid having count(userid)>1)

Answer 2

我稍微修改了上面的内容，使其更加光滑：

WITH combined AS
(
SELECT id from t1
UNION ALL
SELECT id FROM t2
etc...
)
SELECT id, count(id) as numOccurrences
FROM combined
GROUP BY id
HAVING count(id) > 1

不同之处在于，这将显示您的号码重复次数。

你也可以添加

ORDER BY numOccurrences to chop down your worst offenders first

Answer 3

;WITH combined AS (
  SELECT id, title, userid FROM locations
  UNION ALL
  SELECT id, title, userid FROM artists
)
SELECT *
FROM combined c
  INNER JOIN (
    SELECT userid
    FROM combined
    GROUP BY userid
    HAVING COUNT(*) > 1
  ) g ON c.userid = g.userid

从UNION子查询中获取非唯一userid列表，并将其连接回userid上的子查询。子查询仅作为CTE实现一次。

选择多个表上多次出现的行

3 个答案: