eg. user表
| id | name | marker | code |
| 1 | xixi | 001 | aaa |
| 2 | mumu | 001 | bbb |
| 3 | chuchu | 002 | aaa |
| 4 | xinxin | 002 | aaa |
| 5 | huhu | 002 | bbb |
| 6 | yingying | 003 | aaa |
| 7 | tutu | 001 | aaa |
sql语句：
select marker,code,count(code) as count
where marker in ('001','002')
group by marker ,code;
输出结果：
| marker | code | count | |
| 001 | aaa | 2 | |
| 001 | bbb | 1 | |
| 002 | aaa | 2 | |
| 002 | bbb | 1 |