Where does the unknown end up in the lineup?

Question

Accepted Answer

In PostgreSQL, NULLs sort as greater than any non-NULL value, so they appear last in ASC order and first in DESC order. You can override this with NULLS FIRST or NULLS LAST: ORDER BY col ASC NULLS FIRST. Other databases differ - MySQL sorts NULLs first in ASC, so always check your database's behavior and use NULLS FIRST/LAST explicitly when it matters.