Re: [SQL] Mail about select

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От Tom Lane
Тема Re: [SQL] Mail about select
Дата
Msg-id 16871.928506798@sss.pgh.pa.us
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Ответ на Mail about select  (Vikrant Rathore <vikrant@chemquick.com>)
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Vikrant Rathore <vikrant@chemquick.com> writes:
> now i am firing a query like this:

> select r.uname from radius r, radiustemp rt where r.uname<>rt.uname and
> r.logdate<>rt.logdate and r.logtime<>rt.logtime;

> After some time i get  response
> "Segmentation Error"
> core(sumped)

How big are your tables?  That query will probably produce an output
row for almost every combination of a row from radius with a row from
radiustemp, which might overflow the allowed memory for your
application.

I suppose what you really want is to find the rows in radius that do
not have duplicates in radiustemp, but that query won't do it...
        regards, tom lane


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