Re: Search for lists

From: Daron Ryan <daron(dot)ryan(at)gmail(dot)com>
To: David Johnston <polobo(at)yahoo(dot)com>
Cc: "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org>
Subject: Re: Search for lists
Date: 2011-06-19 05:08:31
Message-ID: 4DFD844F.2030901@gmail.com
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Thanks.
On 19/06/2011 8:09 AM, David Johnston wrote:
> An alternative approach would be to select using a IN condition on the where clause and group by column 1 and column 2. Then, using this as a sub-select group by the resultant column 1 and a count on column two. The matching identifiers are those with a count equal to the number of entries in the original IN condition.
>
> Basically count how many of values each distinct key in column 1 matches and keep those keys where the count and the number of values match.
>
> David J.
>
>
> On Jun 18, 2011, at 17:51, Daron Ryan<daron(dot)ryan(at)gmail(dot)com> wrote:
>
>> Hello,
>>
>> I need to search a table to find sets of rows that have a column matching itself for the whole set and another column matching row for row with a list I am going to supply. The result I should receive should be value of the column that matches itself.
>>
>> For example given the following data in my table:
>>
>> 3; 1
>> 3; 2
>> 4; 8
>> 4; 9
>> 4; 10
>>
>> I might need to search for 1,2. This should produce the result 3. Or if I were to search for 8, 9, 10 the result should be 4. Searching for 8, 9 should produce an empty result as should 8, 9, 10, 11.
>>
>> Can anyone recommend a strategy?
>>
>> --
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