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

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    用户贡献的备注 3 notes

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    3
    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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    2
    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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    -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.
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