select PRODUCE_NAME, MARKET_NAME,avg(PRICE) "平均价格" from PRICE p join MARKET m on p.MARKET_ID = m.MARKET_ID join PRODUCE pe on p.PRODUCE_ID = pe.PRODUCE_ID where pe.PRODUCE_NAME = '菠菜' group by PRODUCE_NAME, MARKET_NAME;
由于销售类型表、市场表的字段没有说明,因此不得而知 select produce_id as 产品号,sell_type_id as 销售类型 ,avg(price) as 平均价格 from price join produce on produce.produce_id=price.produce_id where produce.produce_name='菠菜' group by produce_id,sell_type_id 其实中间可以结合case语句会更好
from PRICE p
join MARKET m
on p.MARKET_ID = m.MARKET_ID
join PRODUCE pe
on p.PRODUCE_ID = pe.PRODUCE_ID
where pe.PRODUCE_NAME = '菠菜'
group by PRODUCE_NAME, MARKET_NAME;
select produce_id as 产品号,sell_type_id as 销售类型 ,avg(price) as 平均价格 from
price
join produce
on produce.produce_id=price.produce_id
where produce.produce_name='菠菜'
group by produce_id,sell_type_id
其实中间可以结合case语句会更好