NULL values are placed as follows: ASC , NULLS LAST — NULL values appear at the end of the sorted result. DESC , NULLS FIRST — NULL values appear at the beginning of the sorted result.

How null values are sorted in SQL?

The SQL standard does not explicitly define a default sort order for Nulls. Instead, on conforming systems, Nulls can be sorted before or after all data values by using the NULLS FIRST or NULLS LAST clauses of the ORDER BY list, respectively. This is the case for Oracle RDBMS.

How are NULL values sorted?

If you specify the ORDER BY clause, NULL values by default are ordered as less than values that are not NULL. Using the ASC order, a NULL value comes before any non-NULL value; using DESC order, the NULL comes last.