GROUP BY PRIORITIZE NULL？

Question

表：

 ID                    in                   out
  1   2000-01-01 00:00:00   2000-01-01 12:00:00
  1   2000-01-02 00:00:00                  NULL
  2   2000-01-01 00:00:00   2000-01-01 12:00:00 
  2   2000-01-02 00:00:00   2000-01-02 11:00:00
  3   2000-01-01 00:00:00                  NULL

结果：

 ID                    in                   out
  1   2000-01-02 00:00:00                  NULL
  2   2000-01-02 00:00:00   2000-01-01 11:00:00
  3   2000-01-01 00:00:00                  NULL

所以我想在所有 ID的中获取最新的 in ，并根据ID对它们进行排序。 我尝试了GROUP BY，但似乎得到了有价值的那个。

我目前所拥有的与

类似

SELECT * 
  FROM TABLE 
GROUP BY ID 
ORDER BY OUT IS NULL DESC, OUT DESC;

Answer 1

您需要选择适当的值以及按以下顺序执行订单：

select t.*
from t join
     (select t.id, max(t.in) as maxin
      from t
      group by t.id
     ) tsum
     on t.id = tsum.id and t.in = tsum.maxin
order by id