Re: count function alternative in postgres

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От junaidmalik14
Тема Re: count function alternative in postgres
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Msg-id 28339793.post@talk.nabble.com
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Ответ на Re: count function alternative in postgres  (Ben Morrow <ben@morrow.me.uk>)
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Thanks Ben. It works fine.

Junaid.


Ben Morrow-2 wrote:
> 
> Quoth junaidmalik14@gmail.com (junaidmalik14):
>> 
>> Is there any alternative of mysql function COUNT(DISTINCT expr,[expr...])
>> in
>> postgres. We get error if we 
>> 
>> write count like this count(distinct profile.id, profile.name,
>> profile.age)
>> but it works well in mysql.
> 
> Pg does support COUNT(DISTINCT ), but only for a single column. The best
> I can come up with for multiple columns is
> 
>     select count(distinct profile.tuple) from
>         (select (id, name, age) as tuple from profile)
>             as profile;
> 
> or alternatively
> 
>     select count(*) from
>         (select distinct (id, name, age) as tuple from profile)
>             as profile;
> 
> Ben
> 
> 
> -- 
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> 

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