獲取與參考表不同的狀態相同主鍵列

Question

我有如下表

id task_id stage_id is_completed 
1 1   1  1 
2 1   2  1 
3 1   3  0 
4 2   1  1 
5 2   2  0 
6 2   3  1 
7 3   1  1 
8 3   2  1 
9 3   3  0 

我怎樣才能得到所有task_ids其中stage_id = 1和is_completed = 1和stage_id = 2，is_completed = 0

Answer 1

SELECT *從mt_task_status 其中 TASK_ID在（SELECT TASK_ID FROM mt_task_status WHERE stage_id = '1' 和is_completed = '1'） 和TASK_ID在（SELECT TASK_ID FROM mt_task_status WHERE stage_id = '2' 和is_completed ='0'） and stage_id in（1,2） order by task_id

Answer 2

使用union：

select task_id from table where stage_id = 1 and is_completed = 1 
union 
select task_id from table where stage_id = 2 and is_completed = 0 

Answer 3

您可以使用AND和OR，例如組合：

SELECT task_id 
FROM tasks 
WHERE (stage_id = 1 AND is_completed = 1) 
OR (stage_id = 2 AND is_completed = 2) 
GROUP BY task_id;