Re: Performing antijoin in postgres

"Suresh_" <suiyengar(at)yahoo(dot)com> writes:

> I want to add an antijoin operator to PostgreSql.

I think you can already do what you want like this:

SELECT *
FROM A FULL OUTER JOIN B ON (x=y)
WHERE x IS NULL
OR y IS NULL

So for example:

postgres=# select * from a;
i
---
1
2
(2 rows)

postgres=# select * from b;
i
---
2
3
(2 rows)

postgres=# select * from a full outer join b on (a.i=b.i) where a.i is null or b.i is null;
i | i
---+---
1 |
| 3
(2 rows)

--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com