Re: Search for lists

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От David Johnston
Тема Re: Search for lists
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Msg-id 2CE9F932-85E0-44BC-82D2-A01F98DDB575@yahoo.com
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Ответ на Search for lists  (Daron Ryan <daron.ryan@gmail.com>)
Ответы Re: Search for lists  (Daron Ryan <daron.ryan@gmail.com>)
Список pgsql-general
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
arethose 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
numberof values match. 

David J.


On Jun 18, 2011, at 17:51, Daron Ryan <daron.ryan@gmail.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
matchingrow for row with a list I am going to supply. The result I should receive should be value of the column that
matchesitself. 
>
> 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
shouldbe 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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