mysqli::$field_count

    mysqli_field_count

    (PHP 5, PHP 7, PHP 8)

    mysqli::$field_count -- mysqli_field_count — Returns the number of columns for the most recent query

    说明

    面向对象风格

    int$mysqli->field_count;

    过程化风格

    mysqli_field_count(mysqli$mysql): int

    Returns the number of columns for the most recent query on the connection represented by the mysql parameter. This function can be useful when using the mysqli_store_result() function to determine if the query should have produced a non-empty result set or not without knowing the nature of the query.

    参数

    mysql

    仅以过程化样式：由 mysqli_connect() 或 mysqli_init() 返回的 mysqli 对象。

    返回值

    An integer representing the number of fields in a result set.

    示例

    示例 #1 $mysqli->field_count example

    面向对象风格

    <?php
    $mysqli     = new mysqli("localhost", "my_user", "my_password", "test");

    $mysqli->query( "DROP TABLE IF EXISTS friends");
    $mysqli->query( "CREATE TABLE friends (id int, name varchar(20))");

    $mysqli->query( "INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')");


    $mysqli->real_query("SELECT * FROM friends");

    if (    $mysqli->field_count) {

    $result = $mysqli->store_result();


    $row = $result->fetch_row();


    $result->close();
    }


    $mysqli->close();
    ?>

    过程化风格

    <?php
    $link     = mysqli_connect("localhost", "my_user", "my_password", "test");

    mysqli_query($link, "DROP TABLE IF EXISTS friends");
    mysqli_query($link, "CREATE TABLE friends (id int, name varchar(20))");

    mysqli_query($link, "INSERT INTO friends VALUES (1,'Hartmut'), (2, 'Ulf')");

    mysqli_real_query($link, "SELECT * FROM friends");

    if (    mysqli_field_count($link)) {

    $result = mysqli_store_result($link);


    $row = mysqli_fetch_row($result);


    mysqli_free_result($result);
    }


    mysqli_close($link);
    ?>
    To Top