Syntax
------

identifier = expr

Description
-----------

The equal sign is used as both an assignment operator in certain contexts, and
as a comparison operator. When used as assignment operator, the value on the
right is assigned to the variable (or column, in some contexts) on the left.

Since its use can be ambiguous, unlike the := assignment operator, the =
assignment operator cannot be used in all contexts, and is only valid as part
of a SET statement, or the SET clause of an UPDATE statement

This operator works with both user-defined variables and local variables.

Examples
--------

UPDATE table_name SET x = 2 WHERE x > 100;

SET @x = 1, @y := 2;

URL: https://mariadb.com/kb/en/assignment-operators-assignment-operator/