Re: histogram

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От Thomas Markus
Тема Re: histogram
Дата
Msg-id 4DBD0EB7.8070207@proventis.net
обсуждение исходный текст
Ответ на Re: histogram  (Joel Reymont <joelr1@gmail.com>)
Список pgsql-general
hi,

group by 1 means group by first output column
order by 2 means order by second output column ascending



Am 30.04.2011 19:00, schrieb Joel Reymont:
> What is the meaning of
>
>     group by 1 order by 2
>
> e.g. what to the numbers 1 and 2 stand for?
>
> What would change if I do the following?
>
>     group by 1 order by 1
>
> On Apr 30, 2011, at 5:48 PM, Thomas Markus wrote:
>
>> Hi,
>>
>> try something like this:
>>
>> select
>>     trunc(random() * 10.)/10.
>>     , count(*)
>> from
>>     generate_series(1,2000000)
>> group by 1 order by 2
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