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pg_num_rows

(PHP 4 >= 4.2.0, PHP 5, PHP 7)

pg_num_rows — 返回行的数目

说明

pg_num_rows ( resource $result ) : int

pg_num_rows() 返回 PostgreSQL result 中的行的数目。result 参数是由 pg_query() 函数返回的查询结果资源号。如果出错则返回 -1。

Note:
用 pg_affected_rows() 函数获得被 INSERT，UPDATE 和 DELETE 命令影响到的行的数目。

Note:
本函数以前的名字为 pg_numrows()。

参见 pg_num_fields() 和 pg_affected_rows()。

User Contributed Notes

strata_ranger at hotmail dot com 10-May-2009 10:06


As mentioned, if you are performing an INSERT/UPDATE or DELETE query and want to know the # of rows affected, you should use pg_affected_rows() instead of pg_num_rows().



However, you can also exploit postgres's RETURNING clause in your query to auto-select columns from the affected rows.  This has the advantage of being able to tell not only how many rows a query affects, but exactly which rows those were, especially if you return a primary-key column.



For example:



<?php



// Example query.  Let's say that this updates five rows in the source table.

$res = pg_query("Update foo set bar = 'new data' where foo.bar = 'old data' ");

pg_num_rows($res); // 0

pg_affected_rows($res); // 5

pg_fetch_all($res); // FALSE



// Same query, with a RETURNING clause.

$res = pg_query("Update foo set bar = 'new data' where foo.bar = 'old data' RETURNING foo.pkey");

pg_num_rows($res); // 5

pg_affected_rows($res); // 5

pg_fetch_all($res); // Multidimensional array corresponding to our affected rows & returned columns

?>

ElDiablo 06-Oct-2008 07:09


About preceding note, you shouldn't use pg_num_rows() for this.

You should have instead a look at pg_affected_rows().

francisco at natserv dot com 07-Jan-2008 08:26


Not sure why this documentation doesn't have the following note:

Note: Use pg_affected_rows() to get number of rows affected by INSERT, UPDATE and DELETE query.



Found on other resources. Adding here in case someone else is looking for the info.

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pg_num_rows

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