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/