[thelist] T-SQL join I can't grok

Matt Warden mwarden at gmail.com
Mon Nov 21 18:15:51 CST 2005


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Canfield, Joel wrote:
> (specifically MSSQL in case it matters)
> 
> I have four tables to join in order to get a human-readable list. Here's
> pseudo-code for what I'm looking for:
> 
> select d.document_number, p.permissions, 
> [here's the tricky part]
> (either u.fullname or g.fullname, 
> depending on whether p.object_type is 'g' or 'u')
> from (lotsa joined tables; I can write the joins)
> 
> I just can't get my head around the logic to decide which table to query
> depending on the value of p.object_type for each row returned.

select (case p.object_type when 'g' then g.fullname when 'u' then
u.fullname else NULL END) as fullname
from lotsa l, joined u, tables g
where joelcanwritethejoins=1;


- --
Matt Warden
Miami University
Oxford, OH, USA
http://mattwarden.com


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