Question

I have a table like:

| ID    | Val |
+-------+-----+
| abc-1 |  10 |
| abc-2 |  30 |
| cde-1 |  10 |
| cde-2 |  10 |
| efg-1 |  20 |
| efg-2 |  11 |

and would like to get the result based on the substring(ID, 1, 3) and minimum value and ist must be only the first in case the Val has duplicates

| ID    | Val |
+-------+-----+
| abc-1 |  10 |
| cde-1 |  10 |
| efg-2 |  11 |

the problem is that I am stuck, because I cannot use group by substring(id,1,3), ID since it will then have again 2 rows (each for abc-1 and abc-2)

Answer 1

WITH
  sorted
AS
(
  SELECT
    *,
    ROW_NUMBER() OVER (PARTITION BY substring(id,1,3) ORDER BY val, id) AS sequence_id
  FROM
    yourTable
)
SELECT
  *
FROM
  sorted
WHERE
  sequence_id = 1