I have table with many columns, i interested in column "a", column "b" and column "val". What i need is, to create query, when a is equal to specific int (lets say a=1) and b also equal to specific int (b=1). For every row that match that criteria i want to sum values, that indicated in "val" column. How to create that query?
You should use a group by clause
select a , b , sum(val) from [YourTable] group by a , b having a = 1 and b = 1