Usage of MySQL's “IF EXISTS”

Question

Here are two statements that I\'d like to work, but which return error messages:

IF EXISTS (SELECT * FROM gdata_calendars WHERE `group` =  ? AND id = ?) SELE         


        

Answer 1

You cannot use IF control block OUTSIDE of functions. So that affects both of your queries.

Turn the EXISTS clause into a subquery instead within an IF function

SELECT IF( EXISTS(
             SELECT *
             FROM gdata_calendars
             WHERE `group` =  ? AND id = ?), 1, 0)

In fact, booleans are returned as 1 or 0

SELECT EXISTS(
         SELECT *
         FROM gdata_calendars
         WHERE `group` =  ? AND id = ?)