pg_num_rows

(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)

pg_num_rows — 返回结果中行的数量

说明

pg_num_rows(PgSql\Result $result): int

pg_num_rows() 返回 PgSql\Result 实例中的行的数量。

注意:
本函数以前的名字为 pg_numrows()。

参数

result: PgSql\Result 实例，由 pg_query()、pg_query_params() 或者 pg_execute()（等）返回。

返回值

结果中行的数量。错误时返回 -1。

更新日志

版本	说明
8.1.0	现在 `result` 参数接受 PgSql\Result 实例，之前接受 resource。

示例

示例 #1 pg_num_rows() 示例

<?php
$result = pg_query($conn, "SELECT 1");

$rows = pg_num_rows($result);

echo $rows . " row(s) returned.\n";
?>

以上示例会输出：

1 row(s) returned.

参见

pg_num_fields() - 返回结果中字段的数量
pg_affected_rows() - 返回受影响的记录数（元组）

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＋添加备注

用户贡献的备注 3 notes

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strata_ranger at hotmail dot com ¶

15 years ago

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
?>

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francisco at natserv dot com ¶

16 years ago

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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-1

ElDiablo ¶

16 years ago

About preceding note, you shouldn't use pg_num_rows() for this.
You should have instead a look at pg_affected_rows().