表a字段:aId,aname,表b字段:bId,bname,表c字段:cId,cname,aId,bId.
c表的aId,bId关联a表的aId,b表的bId。a,b,c三表关联查询出a表中所有的aname,b表中所有的bname。
查询结果中,aname,bname不能为null
c表的aId,bId关联a表的aId,b表的bId。a,b,c三表关联查询出a表中所有的aname,b表中所有的bname。
查询结果中,aname,bname不能为null
FROM c, a, b
WHERE c.aid = a.aid AND
c.bid = b.bid AND
a.aname IS NOT NULL AND
b.bname IS NOT NULL;
from a,b,c
where a.aid=c.aid and c.bid=b.bid and a.aname is not null and b.bname is not null
SELECT a.aname, b.bname
FROM c, a, b
WHERE c.aid = a.aid AND c.bid = b.bid AND
a.aname IS NOT NULL AND b.bname IS NOT NULL;--或者是这样?
SELECT a.aname, b.bname
FROM c, a, b
WHERE c.aid(+) = a.aid AND c.bid(+) = b.bid AND
a.aname IS NOT NULL AND b.bname IS NOT NULL;
select a.aname,b.bname
from a ,b , c
where a.aId = c.aId
and b.bId = c.bId
and a.aname is not NULL
and b.bname is not NULL
SELECT a.aname, b.bname
FROM c, a, b
WHERE c.aid = a.aid
AND
c.bid = b.bid
AND
a.aname IS NOT NULL
AND
b.bname IS NOT NULL;
right