What is the difference between = and := in MySQL?

Question

What is the difference in between

set test_var = 20;

and

set test_var:=20;

as they both seem to ass

Answer 1

It's more or less Syntactic sugar.

Take a look here

Most important difference is

Unlike =, the := operator is never interpreted as a comparison operator. This means you can use := in any valid SQL statement (not just in SET statements) to assign a value to a variable.