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