输出记录不重复

Question

我有一个像这样的table，我想在不重复同一用户的情况下输出。如果我使用 group by 它只显示同一列上的一条记录。我还在 location 和 user name 中使用左连接。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     |
+------+---------+----------+---------+

我正在找这个

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

Answer 1

这里您只需要一个不同的子句 -

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

输出记录不重复

Output record without duplicate

mysql

database-design