Question

我有一个带有字段的表job_to_universities

id  univ_id  post_id
1     2        3
2     3        3
3     5        5
4     1        8
5     2        8

我有另一个表job_postings与字段

id(post_id)  is_public
1             1
2             0
3             1
4             1
5             1 
6             0
7             0
8             0

对于5的大学ID，我想从job_postings表中获取所有作业以及job_postings表中is_public为1的作业，我仍然坚持这一点。

Answer 1

SELECT jp.post_id 
FROM job_postings jp, job_to_universities ju 
WHERE jp.id = ju.post_id AND ju.univ_id = 5 AND jp.is_public = 1

Answer 2

如果我理解正确，您希望获得所有公开和与大学相关的职位发布。这意味着一个相当简单的连接：

SELECT ... FROM job_postings NATURAL JOIN job_to_universities
WHERE univ_id = ? AND is_public = 1

如果您希望获得所有公开或与大学相关的职位发布，您可以写下以下内容：

SELECT ... FROM job_postings WHERE is_public = 1 
OR post_id IN (SELECT post_id FROM job_to_universities WHERE univ_id = ?)

或使用UNION DISTINCT：

SELECT ... FROM job_postings WHERE is_public = 1
UNION DISTINCT
SELECT ... FROM job_postings NATURAL JOIN job_to_universities
WHERE univ_id = ?

Answer 3

类似的东西：

SELECT b.id FROM job_to_universities a , job_postings b 
WHERE a.post_id = b.id AND b.is_public = 1 AND a.univ_id = 5

Answer 4

试试这个：

SELECT *
  FROM job_postings b
WHERE 
    (
        id IN (SELECT post_id FROM job_to_universities WHERE univ_id = 5)
        OR 
        is_public = 1
    )

跨两个表构建一个mysql查询

4 个答案: