I have the following table:
create table Likes(ID1 number(5), ID2 number(5));
insert into Likes values(1689, 1709);
insert into Likes values(1709, 1689);
insert into Likes values(1782, 1709);
insert into Likes values(1911, 1247);
insert into Likes values(1247, 1468);
insert into Likes values(1641, 1468);
insert into Likes values(1316, 1304);
insert into Likes values(1501, 1934);
insert into Likes values(1934, 1501);
insert into Likes values(1025, 1101);
The table contains the 'likes' of users identified by their IDs. Liking is a one way connection (If ID1 likes ID2 does not mean that TD2 is liking ID1).
I want to find those IDs, where is a two way connection (where the 'liker' is 'liked back' by user he likes).
I am beginner with Oracle SQL, I hope my question isn't that banal...