Re: new to joins

[Ramalingam Chelliah]

Hi,
Sorry the order of JOIN was given wrongly....

Tables should be joined in this order
contacts ,events ,contacts

( Xeon's reply would give you primary /secondary ID
And for Xeon , this is a hint...
INNER JOIN -order not important
LEFT/RIGHT JOINs ORDER is important
)

Now ,

SELECT X.lastname,Y.lastname,Z.eventcode
FROM
CONTACTS as X
LEFT OUTER JOIN
EVENTS as Z
ON X.contactId = Z.primary_contactId
LEFT OUTER JOIN
CONTACTS as Y
ON Y.contactId= Z.secondary_contactId;

If you don't want to see Null ADD WHERE Condition ...
or A simple INNER JOIN....
(order not important)

SELECT X.lastname,Y.lastname,Z.eventcode
FROM
EVENTS as Z,CONTACTS as X,CONTACTS as Y
WHERE X.contactId=Z.primary_contactId
AND
Y.contactId=Z.secondary_contactId ;


Regards,
Ram.







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