Title: Message
The LEFT OUTER JOIN returns rows in the Subset
table that have no corresponding row in the Master table. Such rows are
indicated by a indicated by a NULL Master.ID column.
So specifying WHERE Master.ID IS NULL isolates
only these rows.
NB This assumes the ID column is not nullable,
which is usually the case with primary/foreign keys used to perform such
joins.
cheers,
Paul.
----- Original Message -----
Sent: Saturday, March 20, 2004 6:09
AM
Subject: RE: [DUG] Programming in Delphi,
but have a SQL question
What
if the JOINed master column is not null? �
Eric Tishler
Software Architect
Resolute Partners,
LLC
Phone: 203.271.1122
Fax: 203.271.1460
[EMAIL PROTECTED]
-----Original
Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]On
Behalf Of Paul Ritchie
Sent: Thursday, March 18, 2004 4:17
PM
To: 'NZ Borland Developers
Group - Delphi List'
Subject:
RE: [DUG] Programming in Delphi, but have a SQL question
I would
tend to use an outer join where the JOINed master column is NULL
eg
SELECT
Subset.*
FROM
Subset
LEFT
OUTER JOIN Master ON Subset.ID = Master.ID
WHERE
Master.ID IS NULL
cheers,
Paul.
-----Original
Message-----
From:
[EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of Eric Tishler
Sent: Friday, 19 March 2004 9:46
a.m.
To: NZ Borland
Developers Group - Delphi List
Subject: [DUG] Programming in Delphi, but
have a SQL question
I am trying to implement a new report in
Delphi, but I am having problems with the query. I know this is not a straight
Delphi question, but I was hoping someone here could steer me in the right
direction.
I have two tables with transactions. One
table contains ALL transactions, the second table is a subset of the first
with only a specific set of transactions. The columns differ between the two
tables, but there is enough relational information for me to match all of the
subset transactions with the master transaction table.
In some odd
cases the subset transaction is inserted, but the corresponding entry is not
added to the master transaction table.
I need to write a query that
shows which transactions in the subset table do not appear in the master
table.
Can someone help me with
this?
Thanks,
Eric
Eric Tishler
Software Architect
Resolute Partners,
LLC
Phone: 203.271.1122
Fax: 203.271.1460
[EMAIL PROTECTED]
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