Question

我的查询与此非常相似。

(SELECT emailid FROM usereducation WHERE presfuncarea = '$funcarea') 
intersect
(SELECT emailid FROM userprofession WHERE totexpyear >= '$minexp')

由于MySQL不支持交叉，我必须找到正确的解决方案。

Answer 1

这应该做的工作：

SELECT p.emailid
FROM usereducation e JOIN userprofession p ON p.emailid = e.emailid
WHERE e.presfuncarea = '$funcarea'
AND p.totexpyear >= '$minexp'

Answer 2

MySQL支持EXISTS。这应该有效：

SELECT UE.emailid
FROM usereducation AS UE
WHERE UE.presfuncarea = '$funcarea'
  AND NOT EXISTS
    (
    SELECT * FROM userprofession AS UP
    WHERE UE.emailid = UP.emailID AND UP.totexpyear >= '$minexp'
    )

Answer 3

来自：http://www.bitbybit.dk/carsten/blog/?p=71

INTERSECT只是一个内连接，我们将一个表的元组与另一个表的元组进行比较，并选择那些同时删除重复项的表。所以

SELECT member_id, name FROM a
INTERSECT
SELECT member_id, name FROM b

可以简单地重写为

SELECT a.member_id, a.name
FROM a INNER JOIN b
USING (member_id, name)

如何在MySQL中实现此查询？

3 个答案: