Question

假设下表，

 cash_id | cav_id |    updated  | status
---------+--------+-------------+---------
   1     |   1    |  2014-10-14 | A
   2     |   2    |  2014-10-14 | A
   3     |   2    |  2014-10-16 | B
   4     |   3    |  2014-10-17 | A
   5     |   3    |  2014-10-17 | B
   6     |   3    |  2014-10-18 | C
   7     |   4    |  2014-10-18 | A
   8     |   5    |  2014-10-19 | A
   9     |   5    |  2014-10-19 | B
  10     |   4    |  2014-10-20 | B
  11     |   5    |  2014-10-21 | c

如您所见，上表有多个cav_id条目，如何获取每个cav_id组的最后更新（cav_id）记录？
意思是，我应该得到以下cash_id条记录： 1,3,6,10,11，......

Answer 1

试试这个：

SELECT *
FROM (
    SELECT *, ROW_NUMBER() OVER (PARTITION BY cav_id ORDER BY updated DESC) seq
    FROM yourTable) dt
WHERE seq = 1;

SQL - 特定组by

1 个答案: