查询sql
select * from
(select t.*, row_number() over(partition by t.em order by t.id desc ) rn
from test.com t )
where rn <=1数据中原数据：
| NAME | ID | SAL | EM | ||
| yang | 1.00 | 1000.00 | 1.00 | ||
| liu | 2.00 | 2000.00 | 1.00 | ||
| wang | 3.00 | 4900.00 | 2.00 | ||
| zhi | 4.00 | 5666.00 | 2.00 | ||
| sha | 5.00 | 6777.00 | 3.00 | ||
| deng | 6.00 | 833.00 | 3.00 | ||
查询结果：
| NAME | ID | SAL | EM | RN | |
| liu | 2.00 | 2000.00 | 1.00 | 1.00 | |
| zhi | 4.00 | 5666.00 | 2.00 | 1.00 | |
| deng | 6.00 | 833.00 | 3.00 | 1.00 | |