NULL and Sorting on BareSQL.com

GREATEST Skips NULL on PostgreSQL and Returns NULL on MySQL

Mon, 26 Oct 2026 00:00:00 +0000

GREATEST(sale_price, list_price) picks the larger of two prices. When one of them is NULL, PostgreSQL still picks the other price, and no other engine does.

GREATEST(1, NULL) is 1 on PostgreSQL and NULL on MySQL and MariaDB. SQLite has the same idea under the names MAX(a, b) and MIN(a, b) with two or more arguments; they return NULL when any argument is NULL, and the other engines read MAX and MIN as aggregates.

NULL Sorts First on SQLite and MySQL and Last on PostgreSQL

Mon, 26 Oct 2026 00:00:00 +0000

Sort customers by the date of their last order and the ones who never ordered come first on SQLite, MySQL and MariaDB and last on PostgreSQL. The first page of the same report shows different people.

The standard leaves the place of NULL in ORDER BY to the engine. PostgreSQL treats NULL as larger than every value, the others as smaller, and descending order turns both around. Paged results change when the column holds NULL, and so do window functions such as ROW_NUMBER() OVER (ORDER BY x).

NULLS FIRST and NULLS LAST Fail on MySQL and MariaDB

Mon, 26 Oct 2026 00:00:00 +0000

ORDER BY shipped_at NULLS LAST is the tidy way to put unshipped orders at the end on PostgreSQL and SQLite. MySQL and MariaDB have no such syntax and refuse the query.

SQLite added them in version 3.30. MySQL and MariaDB have no syntax for choosing where NULL sorts.