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

    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

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    User Contributed Notes 3 notes

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    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
    1
    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
    0
    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().
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