输出记录，无重复

Question

我有一个这样的表，我想输出而不重复同一用户。如果我使用group by它在同一列上只显示一条记录。IAM 还对location和user name使用左联接。一点帮助

+------+---------+----------+---------+
| user | work id | location |  time   |
+------+---------+----------+---------+
|    1 |      42 |        1 | 2hr     |
|    1 |      42 |        1 | 10min   |
|    1 |      42 |        1 | 30min   |
|    2 |      42 |        1 | 4hr     |
|    2 |      42 |        1 | 2.30min |
|    1 |      50 |        2 | 4min    |
|    1 |      50 |        2 | 5min    |
|    2 |      20 |        3 | 3hr     |
|    1 |      20 |        3 | 6hr     |
+------+---------+----------+---------+

我正在寻找这个

+------+---------+----------+
| user | work id | location |
+------+---------+----------+
|    1 |      42 |        1 |
|    1 |      50 |        2 |
|    1 |      20 |        3 |
|    2 |      42 |        1 |
|    2 |      20 |        3 |
+------+---------+----------+

Answer 1

你只需要一个不同的子句 -

SELECT DISTINCT user
,workid
,location
FROM YOUR_TABLE
ORDER BY user
,location