原始数据：
| code | name | z_date |
|---|---|---|
| 1 | aaa | 20241220 |
| 1 | aaa | 20241221 |
| 1 | aaa | 20241222 |
| 2 | bbb | 20241219 |
| 2 | bbb | 20241220 |
输出结果：
| code | name | z_date |
|---|---|---|
| 1 | aaa | 20241220,20241221,20241222 |
| 2 | bbb | 20241219,20241220 |
SQL:
select code,name,count(n),GROUP_CONCAT(z_date order by z_date asc SEPARATOR ', ') from z_data group by code,name order by 3 desc;