Message-ID: <43E877D3.9090509@archonet.com>
Date: Tue, 07 Feb 2006 10:34:59 +0000
From: Richard Huxton <dev@archonet.com>
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To: superboy143 <superboy143@gmail.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: query
References: <2798161.post@talk.nabble.com>
In-Reply-To: <2798161.post@talk.nabble.com>
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superboy143 (sent by Nabble.com) wrote:
> Hello,
> 
> I have a table in which I have a field with format like 100101. It
> has many values like 100101, 100102, 100103, 100201, 100202, 100301.

OK - so they look like numbers but aren't.

> I have to write a query such that I have to get only distinct values
> such that they contain only the substring I need. If I give 10 as
> substring, then it should return only 100101 or 100102 but not both
> i.e if the last two characters are not same it should not return both
> of them. 

The statement of the rule and the example contradict each other. Surely 
100101 and 100102 are distinct values. Surely they contain "10" as a 
substring. So according to your rule the should be returned.

 > It should return only values starting with 10 the middle two
> values should be distinct and the last two characters may be
> anything. 

This seems to agree with your example and not your rule.

So:
1. You don't want distinct values of your field, you want distinct 
substrings of your field?
2. You don't want to match a substring, you want to match the start of 
the string?
3. You want only one of 100101 or 100102 but you don't care which?

Is this correct?

By the way - it looks to me like you are trying to store multiple values 
in one column. If you split the values into their own columns I'd guess 
your query would be much easier.

-- 
   Richard Huxton
   Archonet Ltd