select roomname,a.roomid,cnt
from (select roomid,count(count(*)) cnt from roominfo group by roomid) a,room b
where a.roomid=b.roomid;
from (select roomid,count(count(*)) cnt from roominfo group by roomid) a,room b
where a.roomid=b.roomid;
解决方案 »
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roomid integer,
roomname varchar2(10),
constraint pk_room primary key (roomid)
);create table roominfo(
roomid integer,
member_name varchar2(10),
constraint fk_roominfo foreign key (roomid) references room(roomid) on delete cascade
);begin
for x in 1..10 loop
insert into room values(x,'room'||x);
for y in 1..10 loop
insert into roominfo values(x,'name'||x||y);
end loop;
end loop;
commit;
end;
/select roomname,a.roomid,cnt
from (select roomid,count(*) cnt from roominfo group by roomid) a,room b
where a.roomid=b.roomid;
from qq_room s, roominfo t
where s.roomid=t.roomid
group by s.roomname,s.roomid 不过这样人数为0的房间未显示:如下则可
select s.roomname,s.roomid ,t.GustNum
from qq_room s, (select roomid,count(*) as GustNum from roominfo group by roomid) t
where s.roomid=t.roomid(+)