Oracle EXISTS

From: <cochrane68_at_hotmail.com>
Date: 6 Jun 2005 06:51:14 -0700
Message-ID: <1118065874.206271.123930@g49g2000cwa.googlegroups.com>

I'm having a little trouble understanding the EXISTS operator. Why do the following SQL statements return a different number of records:

SELECT t.id, lt.id
FROM table t, link_table lt
WHERE lt.id(+) = t.id;

SELECT t.id
FROM table1 t
WHERE
EXISTS (

      SELECT 0
      FROM link_table1 lt
      WHERE lt.id(+) = t.id

);

I thought EXISTS basically allows you to join tables in subselect statements, but there appears to be some subtle differences I'm missing. Received on Mon Jun 06 2005 - 08:51:14 CDT