PHPのお勉強!

PHP TOP

pg_num_rows

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

pg_num_rows行数を返す

説明

pg_num_rows(PgSql\Result $result): int

pg_num_rows() は、 PgSql\Result クラスのインスタンスに含まれる行数を返します。

注意:

この関数は、以前は pg_numrows() と呼ばれていました。

パラメータ

result

pg_query()pg_query_params() や (様々な関数がありますが、特に) pg_execute() が返した PgSql\Result クラスのインスタンス。

戻り値

結果の行数を返します。エラー時には -1 を返します。

変更履歴

バージョン 説明
8.1.0 result は、PgSql\Result クラスのインスタンスを期待するようになりました。 これより前のバージョンでは、リソース を期待していました。

例1 pg_num_rows() の例

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

$rows = pg_num_rows($result);

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

上の例の出力は以下となります。

1 row(s) returned.

参考

add a note

User Contributed Notes 3 notes

up
4
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
?>
up
0
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.
up
-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().