Functions for use in the SELECT and WHERE clause
A SELECT or WHERE statement of a SQL command can include any expression that uses the functions described in this section.
An expression that contains a NULL operand always returns NULL as a result, if nothing else is specified in the description of the operator or function.
General operators and functions.
( … ) parenthesis
Allows you to change the order of calculation.
SELECT 2 + 3 * 4 => 14 SELECT (2 + 3) * 4 => 20