Re: [SQL] Finding missing records... - Mailing list pgsql-sql

From wieck@debis.com (Jan Wieck)
Subject Re: [SQL] Finding missing records...
Date
Msg-id m12ONL6-0003kgC@orion.SAPserv.Hamburg.dsh.de
Whole thread Raw
In response to Finding missing records...  (Matthew Hagerty <matthew@venux.net>)
List pgsql-sql
> Greetings,
>
> I have two tables that maintain a 1:1 relationship via an int based primary
> key.  A record in the primary table should never exist without an
> associated record in the secondary table, however somehow this has
> happened.  Can someone demonstrate a query that would show all records in
> the primary table that do not have associated records in the secondary table?
   SELECT att_pk FROM tab_pk WHERE NOT EXISTS       (SELECT att_fk FROM tab_fk WHERE att_fk = att_pk);

   This is the SQL3 referential definition of PENDANT. It'll not   be in the FOREIGN KEY support of 7.0, but we'll
discussif we   implement  it  for 7.1 (even if it will be damned slooooow if   done on every delete/update to an FK
table).


Jan

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