Sams Teach Yourself MySQL in 21 Days, Second Edition

Operators

There are several types of operators: for comparison, arithmetic, logical operations, pattern matching, type casting, and bitwise operations. Let's go through these types one at a time.

Comparison Operators

The comparison operators have their syntax as follows:

• = (equal to)

• <=> (NULL-safe equal to)

• != or <> (not equal to)

• < (less than)

• <= (less than or equal to)

• >= (greater than or equal to)

• > (greater than)

• expr IS [NOT] NULL (is or is not NULL)

• expr IN (expr1, expr2, ...) (expression in range of possible values)

• expr BETWEEN expr_min AND expr_max (expression between two given values)

Comparison operators return 1 if the result of a comparison is true, or 0 if the result is false. Here are a few examples with = (equals):

SELECT 1 = 1 returns ...