Distinct

distinct

SELECT DISTINCT rep_id, component_id
...

[!What does distinct do?]- removes duplicate tuples for all the selected rows

selects all unique tuples of rep_id & component_Id

distinct on

Postgres specific

it doesn't return the first tuple?????

SELECT DISTINCT ON (col1, col2)
  col3
...
ORDER BY (col1, )
LIMIT 1

[!What distinct on does] 1. Run the query 2. At the end, GROUP BY the ON (col)

usually have LIMIT 1 at the end

---

Last update: 2023-04-24