Get result of SHOW WARNINGS

# mysqli::get_warnings

# mysqli_get_warnings

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

mysqli::get_warnings -- mysqli_get_warnings — Get result of SHOW WARNINGS

### 说明

面向对象风格

public function mysqli::get_warnings(): mysqli_warning|false

过程化风格

function mysqli_get_warnings(mysqli `$mysql`): mysqli_warning|false

Returns a singly linked list comprised of mysqli_warning or `false` if there are no warnings. Each object in the list corresponds to a single line from the result of `SHOW WARNINGS`. Calling mysqli_warning::next() will refill the object with the values from the next row.

> 注意: To retrieve warning messages, it is recommended to use the SQL command `SHOW WARNINGS [limit row_count]` instead of this function.

警告

The linked list cannot be rewound or retrieved again.

### 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

Returns a singly linked list comprised of mysqli_warning or `false` if there are no warnings.

### 示例

示例 #1 Traversing the linked list to fetch all warnings

面向对象风格

    <?php

    mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
    $mysqli = new mysqli("localhost", "my_user", "my_password", "world");

    $mysqli->query("SELECT 1/0, CAST('NULL' AS UNSIGNED)");

    if ($mysqli->warning_count > 0) {
        $warning = $mysqli->get_warnings();
        if ($warning !== false) {
            do {
                printf("Error number: %s\n", $warning->errno);
                printf("Message: %s\n", $warning->message);
            } while ($warning->next());
        }
    }

过程化风格

    <?php

    mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
    $link = mysqli_connect("localhost", "user", "password", "test");

    mysqli_query($link, "SELECT 1/0, CAST('NULL' AS UNSIGNED)");

    if (mysqli_warning_count($link) > 0) {
        $warning = mysqli_get_warnings($link);
        if ($warning !== false) {
            do {
                printf("Error number: %s\n", $warning->errno);
                printf("Message: %s\n", $warning->message);
            } while ($warning->next());
        }
    }

以上示例会输出：

    Error number: 1365
    Message: Division by 0
    Error number: 1292
    Message: Truncated incorrect INTEGER value: 'NULL'

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