查询两个表中不同的数据
select ecs_brand.brand_id,ecs_brand.brand_name from 表名ecs_brand where ecs_brand.brand_id not in (select distinct ecs_goods.brand_id from 表名ecs_goods where ecs_goods.is_on_sale = 1 AND ecs_goods.is_alone_sale = 1 AND ecs_goods.is_delete = 0) and ecs_brand.is_show=1

查询两个表中相同的数据

select distinct a.brand_id,a.brand_name from ecs_brand a,ecs_goods b where a.is_show=1 and b.is_on_sale = 1 and b.is_alone_sale = 1 and b.is_delete = 0 and a.brand_id = b.brand_id

查询两个表中不同（相同）的数据，并把它们显示出来