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ru.cgi.perl
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From : Michael Poliakov 2:5020/400 16 Mar 2001 12:51:37
To : All
Subject : Re: Узнать количество строк в запросе (MySQL)?
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On Thu, 15 Mar 2001 11:57:55 +0000 (UTC), "Dmitry" <dimsan@atnet.ru> wrote:
>Как узнать количество записей которые выбрал запрос одной функцией?
Из perldoc DBI:
rows
$rv = $sth->rows;
Returns the number of rows affected by the last row affecting command, or -1 if
the number of rows is not known or not available.
Generally, you can only rely on a row count after a non-SELECT execute (for some
specific operations like UPDATE and DELETE), or after fetching all the rows of a
SELECT statement.
For SELECT statements, it is generally not possible to know how many rows will
be returned except by fetching them all. Some drivers will return the number of
rows the application has fetched so far, but others may return -1 until all rows
have been fetched. So use of the rows method or $DBI::rows with SELECT
statements is not recommended.
One alternative method to get a row count for a SELECT is to execute a ``SELECT
COUNT(*) FROM ...'' SQL statement with the same ``...'' as your query and then
fetch the row count from that.
Вообще-то это скорее офтопик здесь.
Michael Poliakov
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Re: Узнать количество строк в запросе (MySQL)?