NULL values in ORDER BY

Question

Accepted Answer

In PostgreSQL, NULLs sort last for ASC and first for DESC by default. The SQL standard treats NULLs as greater than any other value for sorting purposes. You can override this with NULLS FIRST or NULLS LAST: ORDER BY salary ASC NULLS FIRST puts NULLs at the top even in an ascending sort. MySQL sorts NULLs first for ASC, which differs from PostgreSQL - always test when portability matters.