Subquery EXISTS NOT EXISTS

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December 23rd, 2004, 08:36 PM

hizar

Registered User

Join Date: Dec 2004

Posts: 3

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Subquery EXISTS NOT EXISTS

Hi guys...got a problem here....

I got a query which joins two table....

Individual
fid1
fQSname
fQSRegno

Point
fid2
fQSRegno
fQSPoint

Tables join using fQSRegno.
Scenario is

Tbl Individual contains all the members info.
Tbl Point contains point given to members who attend courses.

Problem is when I created a query...

Query1
fid3
fQSname
fQSRegno *from tblPoint
fQSPoint

the data shows only members who got points. Is it possible to include member who don't have point like new registred member to show in this query....

TQ

December 25th, 2004, 04:36 PM

A2k

Contributing User

Join Date: Dec 2004

Posts: 166

Time spent in forums: 18 h 44 m 10 sec
Reputation Power: 5

Yes, you need to do what is known as an outer join on the 'Individual' table. This will list all of the individuals regardless of whether they have a 'point' record or not. Check out the syntax for your SQL Environment, but as a guide, the following code is how I would do it, and is pretty universal in its notation:

Code:


Select * 
From Point, Individual
Where fid1 =* fid2

the above should fill a NULL into the spaces where there are no records for the FID2 field.

N.B. As a rule the * in a *= join always is on the side where you wish to insert NULL records.

December 26th, 2004, 12:52 AM

Memnoch

Unholy Moderator

Join Date: Oct 2003

Location: In hell, where did you think?

Posts: 11,879

Time spent in forums: 3 Weeks 5 Days 18 h
Reputation Power: 500

try this

Code:

SELECT A.fQSname,
	B.fQSPoint
FROM Individual As A
LEFT OUTER JOIN Point As B On (A.fQSRegno = B.fQSRegno)
ORDER BY A.fSQname

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