Number Crunching

A little arithmetic can go a long way in SQL. The language includes the math functions that you would expect to find in any computer language, plus a few that are peculiar to databases. It includes functions such as ISNULL, COALESCE, and NULLIF, which help to deal with NULLs. It also includes the aggregating functions such as COUNT, SUM, MAX, MIN, and AVG that are used in GROUP BY queries.