Joining multiple tables in a view.

I have three tables

1^st table is Student

StudnetID (pk)

Other fields…

2^nd table is PhoneType

PhoneTypeID (pk)

PhoneType

3^rd table is StudentHasPhone

SHPID (pk)

StudnetID (fk)

PhoneTypeID (fk)

PhoneNumber

PhoneType is an auxiliary table that has 5 records in it Home phone, Cell phone, Work phone, Pager, and Fax. Is there a way to do a join or maybe make a view of a view that would allow me to ultimately end up with…

StudnetID: 1

Name: John

HomePhone: 123-456-7890

WorkPhone: 123-456-7890

CellPhone:

Pager: 123-456-7890

Fax:

Memo: This is one student record.

Some students will have no phone number, some will have all 5 most will have one or two. If possible I would like to do a setup like this in my database to keep from having to have null fields for 4 phone numbers that the majority of records won't have.

Thanks in advanced,

Nathan Rover

What you need is a View with UNION ALL but your tables must be UNION compatible which means same data type facing the same direction. Try the link below for sample code. Hope this helps.

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/tsqlref/ts_create2_30hj.asp

|||

You can join to the phone table multiple times, as follows:

SELECT StudentID, HP.PhoneNumber, WP.PhoneNumber, CP.PhoneNumber, Pg.PhoneNumber, Fx.PhoneNumber
FROM Student S
LEFT OUTER JOIN StudentHasPhone HP
ON S.StudentID = HP.StudentID
AND HP.PhoneTypeID = 1 --Home Phone
LEFT OUTER JOIN StudentHasPhone WP
ON S.StudentID = WP.StudentID
AND WP.PhoneTypeID = 2 --Work Phone
LEFT OUTER JOIN StudentHasPhone CP
ON S.StudentID = CP.StudentID
AND CP.PhoneTypeID = 3 --Cell Phone
LEFT OUTER JOIN StudentHasPhone Pg
ON S.StudentID = Pg.StudentID
AND Pg.PhoneTypeID = 4 --Pager
LEFT OUTER JOIN StudentHasPhone Fx
ON S.StudentID = Fx.StudentID
AND Fx.PhoneTypeID = 5 --Fax

BTW: StudentHasPhone is not a good table name. StudentPhone, or simply Phone, would be much better.

|||

Thanks, that was exactly what I was looking for… It worked perfect.

--Nathan