Question

作为sql的初学者，我在PostgreSQL中有一个如下表所示。

id  product type  occured_at                  
 1        A    6  2017-03-17 10:21:22.935278
 1        B    6  2017-04-17 10:21:22.941801
 1        B    8  2017-04-17 10:21:22.935278 
 1        B    8  2017-05-17 10:21:22.935278
 1        D    8  2017-06-17 10:21:22.935278
 2        C    4  2017-04-24 10:21:22.938517   
 3        A    8  2017-04-27 10:21:22.941801  
 4        C    8  2017-09-17 10:21:22.941801  
 4        C    6  2017-09-17 10:21:22.941801
 5        D    8  2017-09-17 10:21:22.941801

问题是我如何获得在同一天发生的不同类型的ID和产品。就像

id  product     
 1        B
 4        C

如果有人可以帮助我，我真的很感激：）

Answer 1

 SELECT product  
 FROM YourTable
 GROUP BY product
          date_trunc('dat', occured_at)
 HAVING count(DISTINCT type) > 1

Answer 2

自我加入是一种方法：

SELECT DISTINCT A.ID, A.Product
FROM YourTable A
JOIN YourTable B ON A.ID = B.ID
                AND A.Product = B.Product
                AND DATE(A.Occured_at) = DATE(B.Occured_at)
                AND A.Type <> B.Type

如何获得另一行中也出现的值行？

2 个答案: