我有以下字段:
| employee_email | status | id |
| <a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="0f7b6a7c7b3e4f7b6a7c7b216c6062" rel="noreferrer noopener nofollow">[email protected]</a> | active | 1 |
| <a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="c2b6a7b1b6f382b6a7b1b6eca1adaf" rel="noreferrer noopener nofollow">[email protected]</a> | terminated | 2 |
| <a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="46322335327406322335326825292b" rel="noreferrer noopener nofollow">[email protected]</a> | active | 3 |
| <a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="c1b5a4b2b5f281b5a4b2b5efa2aeac" rel="noreferrer noopener nofollow">[email protected]</a> | terminated | 4 |
| <a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="b6c2d3c5c282f6c2d3c5c298d5d9db" rel="noreferrer noopener nofollow">[email protected]</a> | terminated | 5 |
| <a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="d2a6b7a1a6e692a6b7a1a6fcb1bdbf" rel="noreferrer noopener nofollow">[email protected]</a> | terminated | 6 |
我需要使用以下规则进行查询:同一员工电子邮件是否有超过 1 行(其中一行处于事件状态，另一行已终止 - 则仅返回行 = 事件)。如果超过 1 行并且都终止，则仅返回终止的一行。
输出应该是:
| employee_email | status | status |
| <a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="ff8b9a8c8bcebf8b9a8c8bd19c9092" rel="noreferrer noopener nofollow">[email protected]</a> | active | 1 |
| <a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="f88c9d8b8ccab88c9d8b8cd69b9795" rel="noreferrer noopener nofollow">[email protected]</a> | active | 3 |
| <a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="2f5b4a5c5b1c6f5b4a5c5b014c4042" rel="noreferrer noopener nofollow">[email protected]</a> | terminated | 4 |
| <a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="86f2e3f5f2b2c6f2e3f5f2a8e5e9eb" rel="noreferrer noopener nofollow">[email protected]</a> | terminated | 5 |
最佳答案
如果您的 MySql 版本是 8.0+，您可以使用窗口函数 ROW_NUMBER():
SELECT t.employee_email, t.status, t.id
FROM (
SELECT *, ROW_NUMBER() OVER (PARTITION BY employee_email ORDER BY status = 'active' DESC, id) rn
FROM tablename
) t
WHERE t.rn = 1
对于以前的版本:
SELECT t.employee_email, MAX(t.status) status, MIN(t.id) id
FROM tablename t
WHERE t.status = 'active'
OR NOT EXISTS (SELECT 1 FROM tablename WHERE employee_email = t.employee_email AND status = 'active')
GROUP BY t.employee_email
请参阅demo .
结果:
> employee_email | status | id
> :------------- | :--------- | -:
> <a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="dfabbaacabee9fabbaacabf1bcb0b2" rel="noreferrer noopener nofollow">[email protected]</a> | active | 1
> <a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="6b1f0e181f592b1f0e181f45080406" rel="noreferrer noopener nofollow">[email protected]</a> | active | 3
> <a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="2c58495f581f6c58495f58024f4341" rel="noreferrer noopener nofollow">[email protected]</a> | terminated | 4
> <a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="cdb9a8beb9f98db9a8beb9e3aea2a0" rel="noreferrer noopener nofollow">[email protected]</a> | terminated | 5
关于Mysql 查询具有一行或多行一种状态优先 Mysql 5.7，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/64051999/