如何在表

Question

我想知道如何在表格中第一次找到事件。在这种情况下，当检查变为1

---------------------------
Client Id   | Check | Week
---------------------------
1             0       1
3             1       1
1             0       2
1             1       3
3             1       2

假设这是整个表，查询的结果应该给我

-----------------
Client id    | week
-----------------
1              3
3              1

检查只能是0或1 感谢

Answer 1

SELECT client_id, MIN(Week) AS first_occur
FROM table
WHERE check = 1
GROUP BY client_id