Subject: varchar value comparisons not working?
From: Shawn Tayler <stayler@washoecounty.us>
Reply-To: stayler@washoecounty.us
To: pgsql-sql@postgresql.org
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Organization: Washoe County Regional Communications System
Date: Fri, 24 Apr 2009 06:59:30 -0700
Message-Id: <1240581570.21067.18.camel@shop.telecom.co.washoe.nv.us>
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Hello,

I'm doing a quick comparison between a couple tables, trying to cleanup
some inconsistencies, and what should be a simple check between 2 tables
doesn't seem to be working.  psql is 8.3.7 and server is 8.2.13.

I run the following:

select sfd.lid as sflid,sd.lid as slid,sfd.serial from sfd,shawns_data
sd where sfd.serial = sd.serial_number order by sfd.lid; 

the lid columns in both tables should be identical, but as you see in
this sample, they do differ:

 sflid | slid  |  serial  
-------+-------+----------
 14056 | 14056 | 9614583
 14057 |       | 9614984
 14058 | 14058 | 9614737
 14059 | 14059 | 9614579
 14060 |       | 9614827
 14061 | 14061 | 9614726
 14062 | 14062 | 9614966
 14063 | 14063 | 9615079

So running this query:

select count(*) from sfd,shawns_data sd where sfd.serial = sd.serial_number and sfd.lid != sd.lid; 

I should show some rows that do not match, at least 2 (there are more than shown).  

But instead I get this:

 count 
-------
     0
(1 row)


What am I doing wrong?


-- 
Sincerely,

Shawn Tayler
Radio Network Administrator
Washoe County Regional Communications System
Telecommunications Division
Technology Services Department
County of Washoe
State of Nevada
Ofc  (775)858-5952
Cell (775)771-4241
FAX  (775)858-5960