Question

我有这样的表

user_id    workplace
1          Microsoft
1          Google
2          eBay
3          Panadora
3          Netflix

我想要的是这样一张桌子：

user_id   places_worked
1        Microsoft,Google
2        eBay
3        Panadora,Netflix

在SQL中是否可以做到这一点？

Answer 1

正如@jarlh所提到的，你可以使用group_concat

来做到这一点

 SELECT user_id,GROUP_CONCAT(workplace)
    FROM yourtable
    GROUP BY user_id;

Answer 2

您可以使用group by with group concat operation

SELECT user_id，GROUP_CONCAT（工作区）从yourtable GROUP BY user_id;

检查以下示例

select * from payments;
+----+------------+---------+-------+
| id | date       | user_id | value |
+----+------------+---------+-------+
|  1 | 2016-06-22 |       1 |    10 |
|  2 | 2016-06-22 |       3 |    15 |
|  3 | 2016-06-22 |       4 |    20 |
|  4 | 2016-06-23 |       2 |   100 |
|  5 | 2016-06-23 |       1 |   150 |
+----+------------+---------+-------+
5 rows in set (0.00 sec)


select c.user_id,group_concat(p.value) from calls c inner join payments p on p.user_id=c.user_id group by c.user_id;
+---------+-----------------------+
| user_id | group_concat(p.value) |
+---------+-----------------------+
|       1 | 10,150,10,150,10,150  |
|       2 | 100                   |
+---------+-----------------------+
2 rows in set (0.00 sec)

使用sql将一些列值放入新列中

2 个答案: