Re: GROUP BY column alias?

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От Scott Bailey
Тема Re: GROUP BY column alias?
Дата
Msg-id 4B7DC4BE.6010409@comcast.net
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Ответ на Re: GROUP BY column alias?  ("Eric B. Ridge" <ebr@tcdi.com>)
Ответы Re: GROUP BY column alias?  ("Eric B. Ridge" <ebr@tcdi.com>)
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Eric B. Ridge wrote:
> On Feb 18, 2010, at 4:31 PM, Scott Bailey wrote:
>> I'm not sure why you would be surprised by that behavior. You are grouping by a timestamp, so any microsecond
differencewill be a new group. 
>
> I get that. ;)  Hence the ::date.  This is what doesn't make sense:
>
> Expected:     select day::date as bar, count(*) from foo group by bar;
> Not Expected: select day::date as day, count(*) from foo group by day;
>
> If I alias it to something other than the actual column name, it does what I expect.  But if I alias it to the column
name,it doesn't. 
>
> I would have thought that the precedence rules would resolve the alias first, then the column name, but that doesn't
seemto be the case. 

SQL name resolution rules are that column names have higher precedence
than aliases and variables. So it will always bind to the column not the
alias.

Scott

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