MySql SUM() function

Question

Is it possible to use MySql SUM() function inside another MySql SUM() function ??

Like below

$query="SELECT SUM(Table1.Column1+SUM(Table2.Column2+Table2.Column3)) 
        from Table1 LEFT JOIN Table2 ON Table1.id = Table2.table1_id 
        WHERE Table1.Column2='Test'";

Thanks

Answer 1

From basic math a + b + c = a + (b + c)

So just use one sum. It will be equivalent with what you are doing there ..

Answer 2

You just need one SUM():

SELECT SUM(Table1.Column1 + Table2.Column2 + Table2.Column3) ...

Or use SUM() on each field:

SELECT SUM(Table1.Column1) + SUM(Table2.Column2) + SUM(Table2.Column3) ...