SEND(SEND_ID,BUER_ID,BUYER_ADDRESS) 这个表的的第二个字段应该是BUYER_ID吧 select a.book_id,b.buyer_name,c.buyer_address from book a,buyer b,send c where a.buyer_id=b.buyer_id and c.buyer_id=b.buyer_id
select a.book_id,b.buyer_name,c.buyer_address from book a inner join buyer on a.buyer_id=b.buyer_id inner join send c on b.buyer_id=c.buyer_id
select a.book_id,b.buyer_name,c.buyer_address from book a left join buyer b on a.buyer_id=b.buyer_id left join send c on a.buyer_id=c.buyer_id
select a.book_id,b.buyer_name,c.buyer_address from book inner join buyer b on a.buyer_id=b.buyer_id inner join send c on c.buyer_id=b.buyer_id
select a.book_id,b.buyer_name,c.buyer_address from book a,buyer b, send c where (a.buyer_id = b.buyer_id) and ( b.buyer_id = c.buyer_id)
select a.book_id,b.buyer_name,c.buyer_address from book a left join buyer b on a.buyer_id=b.buyer_id left join send c on a.buyer_id=c.buyer_id
select a.book_id,b.buyer_name,c.buyer_address from book a inner join buyer b on a.buyer_id=b.buyer_id inner join send c on c.buyer_id=b.buyer_id
select A.BOOK_ID,B.BUY_NAME,C.BUYER_ADDRESS from BOOK A left join BUYER B on A.BUYER_ID = B.BUYER_ID left join SEND C on A.BUER_ID = C.BUER_ID
主要还是看这几个表的关系来确定用inner join 还上Left join 的
select A.BOOK_ID,B.BUY_NAME,C.BUYER_ADDRESS from BOOK A left join BUYER B on A.BUYER_ID = B.BUYER_ID left join SEND C on A.BUYER_ID = C.BUYER_ID 这样写,试试!
这个表的的第二个字段应该是BUYER_ID吧
select a.book_id,b.buyer_name,c.buyer_address
from book a,buyer b,send c
where a.buyer_id=b.buyer_id and c.buyer_id=b.buyer_id
from book a inner join buyer on a.buyer_id=b.buyer_id
inner join send c on b.buyer_id=c.buyer_id
from book a,buyer b, send c
where (a.buyer_id = b.buyer_id) and ( b.buyer_id = c.buyer_id)
left join BUYER B on A.BUYER_ID = B.BUYER_ID
left join SEND C on A.BUER_ID = C.BUER_ID
left join BUYER B on A.BUYER_ID = B.BUYER_ID
left join SEND C on A.BUYER_ID = C.BUYER_ID
这样写,试试!