DECLARE @u_cPoints int, @c_creditPoints int;
DECLARE cpoints_cursor CURSOR FOR
    SELECT *
    FROM CreditPoints, Users
    WHERE CreditPoints.userId=Users.userId
OPEN cpoints_cursor;

FETCH NEXT FROM cpoints_cursor
    INTO @u_cPoints, @c_creditPoints;

    WHILE @@FETCH_STATUS = 0
        BEGIN
            UPDATE Users
            SET Users.cPoints = Users.cPoints + @c_creditPoints;
            FETCH NEXT FROM cpoints_cursor
                INTO @u_cPoints, @c_creditPoints;
        END;
    CLOSE cpoints_cursor
    DEALLOCATE cpoints_cursor;
GO