按行显示的合计

select     game,     sum(purchase) as purchase_sum from    purchase group by     game;

按列显示的合计

select     sum(case when game = 'action'             then purchase else 0 end) as sum_action,    sum(case when game = 'puzzle'             then purchase else 0 end) as sum_puzzle,    sum(case when game = 'RPG'             then purchase else 0 end) as sum_rpg from     purchase;