SQL NULLS FIRST

Forces NULL values to the top of the sort, overriding the default placement.

What & Why

By default in Postgres, ORDER BY ... ASC puts NULLs last (NULLs are treated as larger than any real value). NULLS FIRST overrides that, forcing them to the top regardless of sort direction.

See How It Works

BUSINESS QUESTION

Sort product feedback by nps_score and deliberately place missing scores first.

id	user_id	feature_id	rating	nps_score	comment	created_at
1	101	1	5	9	Clear and useful	2024-01-25 12:15:00+00
2	102	2	4	NULL	Export worked well	2024-02-20 15:40:00+00
3	103	1	4	7	Helpful setup flow	2024-03-18 09:05:00+00
4	104	3	3	NULL	Needs clearer timing	2024-04-08 17:30:00+00

EXAMPLE QUERY

SELECT id, user_id, nps_score FROM product.feedback
ORDER BY nps_score ASC NULLS FIRST;

RESULT — NULLs first

id	user_id	nps_score
2	102	NULL
4	104	NULL
3	103	7
1	101	9

NULLS FIRST moves missing scores before known numeric values.

Beginner business practice