create table 库存表 as select b.品名 as 品名,a.suma as 出数量,b.sumb as 进数量,(b.sumb-a.suma) as 库存 from (select 品名,sum(数量) as suma from 出货表 group by 品名) as a right join (select 品名,sum(数量) as sumb from 进货表 group by 品名) as b on a.品名=b.品名;直接执行上面的sql语句,就可以获得新表:库存表。