Conditional Join - join 1 tables 2 ways

Posted by Jon H on Stack Overflow See other posts from Stack Overflow or by Jon H
Published on 2013-10-21T09:50:34Z Indexed on 2013/10/21 9:53 UTC
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c#

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sql

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join

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foxpro

I have a set of (not very well normalised or relational) tables named PLAN, GROUP, PRODUCT CLIENT

Most have linkage i.e. PLAN -> CLIENT on clno GROUP to PRODUCT on PRODCD

However, the linkage between PLAN and GROUP is tricky. A plan has 2 field of interest GRPNO and PRODCD.

What I want to do is if GRPNO != 0 then join GROUP on GRPNO. However if GRPNO = 0 then I want to join GROUP on PRODCD.

The frustrating thing is that the fileds I want to return in my queries are the same across the board I just need to be able to vary the join, or join the same table twice.

The best I can come up with is 2 queries and merge them using datasets, or possibly using a union.

Is there a nifty way to do this in one select?

I should point out I am access Foxpro over ODBC to do this.

Thank you!

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