By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.
| id | customer | total |
|---|---|---|
| 1 | Joe | AA |
| 2 | Sally | CC |
| 3 | Joe | BB |
| 4 | Sally | DD |
| FIRST(id) | customer | FIRST(total) |
|---|---|---|
| 1 | Joe | AA |
| 2 | Sally | CC |
| id | customer | total |
|---|---|---|
| 1 | Joe | AA |
| 2 | Sally | CC |
| 3 | Joe | BB |
| 4 | Sally | DD |
| FIRST(id) | customer | FIRST(total) |
|---|---|---|
| 1 | Joe | AA |
| 2 | Sally | CC |