Re: Arrays

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От Merlin Moncure
Тема Re: Arrays
Дата
Msg-id CAHyXU0y_JC3iBTR2KqKsw5ex-VPRALY5aZVvKiurbYdYaTwVmA@mail.gmail.com
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Ответ на Re: Arrays  (Fabrízio de Royes Mello <fabriziomello@gmail.com>)
Список pgsql-general
On Wed, Sep 14, 2011 at 1:05 PM, Fabrízio de Royes Mello
<fabriziomello@gmail.com> wrote:
>
> 2011/9/14 Bob Pawley <rjpawley@shaw.ca>
>>
>> Hi
>>
>> Is there a method of counting the number of elements in an array??
>>
>
> Yes...
> Use function array_upper [1].
> See an example:
> postgres@bdteste=# SELECT array_upper(ARRAY['foo', 'bar'], 1);
>  array_upper
> -------------
>            2

that only gives you one dimension's worth elements, and only is
correct if the array is 1 based.

select count(*) from unnest(_array_);

will give you an exact count.  another way to do it which doesn't
require expanding the array would be to parse and calculate # elements
from the output of array_dims() (which is unfortunately returned as
text).

merlin

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