SQL GROUP BY



[HAVING](https://texonom.com/having-d431c31ee1c541a7a85b125661c7b125)

- delete duplicated rows
```typeSELECT a.* FROM blur_residue AS aLEFT JOIN blur_residue AS bON a.pvrid = b.pvridGROUP BY a.pvrid HAVING COUNT(a.pvrid) = 4```
하고 heidi 에서 그냥 지우기



