Re: Expressing a result set as an array (and vice versa)?

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От george young
Тема Re: Expressing a result set as an array (and vice versa)?
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Msg-id 20060325221102.31de88d7.gry@ll.mit.edu
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Ответ на Expressing a result set as an array (and vice versa)?  (Don Maier <dMaier@genome.stanford.edu>)
Ответы Re: Expressing a result set as an array (and vice versa)?  (Volkan YAZICI <yazicivo@ttnet.net.tr>)
Список pgsql-sql
On Thu, 23 Mar 2006 11:44:32 -0800
Don Maier <dMaier@genome.stanford.edu> threw this fish to the penguins:

> Is it possible to construct an array from an appropriate select  
> expression that generates a result set of unknown cardinality?
> To focus on the simple case:  Is it possible to construct a one- 
> dimensional array from a select of a single column in a table with an  
> unknown number of rows?
  select array(select some_int_field from my_table where something);

produces an array of integers.  No user defined function is required.

> Conversely, is it possible to construct a (single column) result set  
> from a select expression on a one-dimensional array with an unknown  
> number of elements?
Not so easy without a custom function.

> Thanks for any hints!
> 
> Regards,
> Don Maier
> 
> 
> 
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