- Don't forget
GROUP BYclause when using aggregationaggregate functions. - Your inner SUMs aren't aliased, so
x.quantitywouldn'twon't work.
Try this :
SELECT x.productName, SUM(x.quantity) as quantity FROM ( SELECT productName, SUM(quantity*10) as quantity FROM Sample WHERE description IN ('GT','GE') GROUP BY productName UNION ALL SELECT productName, SUM(quantity*20) as quantity FROM Sample WHERE description IN ('VD') GROUP BY productName ) AS x GROUP BY x.productName