RE: SQL Help finding missing records

Caveat emptor!!

Remember that NOT EXISTS, as well as NOT IN, forces a table scan - you can't tell if something is not there unless you look at everything. Learned this at the last COMMON, I think.

Now probably and EXCEPTION JOIN can do better, IF you have supporting indexes.

Regards
Vern

-------------- Original message --------------
From: "DeLong, Eric" <EDeLong@xxxxxxxxxxxxxxx>

Hi Doug,

Sounds line a job for EXCEPTION JOIN......
Select detl.* from detl exception join hdr on (detl.key=hdr.key)

though there are many other alternatives....
Select detl.* from detl where not exists (select * from hdr where
hdr.key = detl.key)

The second version, using the "not exists" clause is actually the more useful of
the two solutions, because it is compatible with other SQL verbs beside
SELECT.... For example, if you wanted to delete these orphaned records, you
would NOT be able to do it with the exception join.... not allowed...

Delete from detl where not exists (select * from hdr where hdr.key =
detl.key)

hth,
Eric DeLong

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx]On Behalf Of Doug Palme
Sent: Wednesday, July 16, 2008 9:19 AM
To: RPG Midrange L
Subject: SQL Help finding missing records


I know I can do this with query, but in the spirit of learning - I would
prefer to do this with SQL.

I have two files SLSTRNHDRF - header file and SLSTRAN - Detail
file.....apparently we have some detail records that do not have a
corresponding header record and I want to double check the file and see if
there any more......I thought I could do it by querying the header file
for account / invoice records that do not match account and invoice fields
in the slstran.....but that did not seem to work.....

Suggestions?


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