Where operators can be used
Comparison operators and functions can appear as conditions, such as part of the WHERE
clause or join ON
conditions. In addition, they can appear in the SELECT
list or other locations where expressions can appear. In the latter case, they return 0 if false, 1 if true, and NULL if an input is NULL. For example:
SELECT t, t LIKE 'r%', t != 'red' FROM s WHERE t = 'red'; **** +------+-------------+------------+ | t | t LIKE 'r%' | t != 'red' | +------+-------------+------------+ | red | 1 | 0 | +------+-------------+------------+