Question

The ____________________ keywords can be included in an ORDER BY clause to indicate that NULL values should be listed last in the results.

A) FIRST
B) LAST
C) NULLS FIRST
D) NULLS LAST

Answer 1

Option (D), The correct keywords to use in an ORDER BY clause to ensure NULL values appear last are 'NULLS LAST'. This allows explicit control of the placement of NULL values in the sorted results of a SQL query.

Step-by-step explanation:

The NULLS LAST keywords can be included in an ORDER BY clause to indicate that NULL values should be listed last in the results. When sorting data in SQL, the ORDER BY clause is used to define the order of the rows returned in a query result set. It can sort the results in ascending (ASC) or descending (DESC) order. By default, many SQL databases sort NULL values first when ascending order is specified, and last when descending order is specified. However, if explicit control is needed over the placement of NULL values, the keywords NULLS FIRST or NULLS LAST can be used. For example, a command like SELECT * FROM table_name ORDER BY column_name DESC NULLS LAST; will show all the non-NULL values first, sorted in descending order, followed by NULL values at the end of the result set.