Question

如果表格包含以下数据

 num   | date_       |           s            | i_id 
-------+-------------+------------------------+---------
     1 | 2013-12-12  | (2,1,2013-12-12,80.56) |       2
     1 | 2013-12-12  | (3,1,2013-12-12,70.56) |       3
     1 | 2013-12-10  | (4,1,2013-12-10,90.76) |       4
     2 | 2013-12-10  | (5,2,2013-12-10,90.76) |       5
     2 | 2013-12-06  | (6,2,2013-12-06,90.76) |       6
     3 | 2013-12-06  | (7,3,2013-12-06,90.76) |       7
     3 | 2013-12-06  | (8,3,2013-12-06,90.76) |       8

我想要一个查询，它会为具有相同num的不同日期的记录提供num，i_id。它应该返回num-1,2和相应的i_id。我该怎么办？

Answer 1

select num, group_concat(i_id) as iids
from your_table
group by num
having count(distinct date_) > 1

Answer 2

这应该适用于PostgreSQL，版本号> gt = = 9.0

SELECT
  num
, array_to_string(array_agg(i_id ORDER BY num), ',')
FROM a
GROUP BY num

参见演示http://sqlfiddle.com/#!15/25502/5

在您的评论中，您希望获得MAX（日期_）

SELECT
  num
, MAX(date_)
, array_to_string(array_agg(i_id ORDER BY num), ',')
FROM a
GROUP BY num

参见演示http://sqlfiddle.com/#!15/25502/6

如何在sql中消除相同的日期值

2 个答案: