I tried your query, and it worked just fine, after some slight tweak: http://sqlfiddle.com/#!2/a6220/4
The final query should look like this:
SELECT (SUM(IFNULL(add,0)))-(SUM(IFNULL(sub,0)))
AS bal FROM ".$table5."
You forgot to add a )
, and also, you had spaces after SUM(). SUM is a function, and should therefore not have any spaces before the ()
.