mysqli_result::$field_count()

(PHP 5, PHP 7)

Get the number of fields in a result

说明

面向对象风格
int $mysqli_result->field_count;

过程化风格
mysqli_num_fields(mysqli_result$result): int

Returns the number of fields from specified result set.

参数

$result: 仅以过程化样式：由mysqli_query()，mysqli_store_result()或mysqli_use_result()返回的结果集标识。

返回值

The number of fields from a result set.

范例

Example #1 面向对象风格

<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}
if ($result = $mysqli->query("SELECT * FROM City ORDER BY ID LIMIT 1")) {
    /* determine number of fields in result set */
    $field_cnt = $result->field_count;
    printf("Result set has %d fields.\n", $field_cnt);
    /* close result set */
    $result->close();
}
/* close connection */
$mysqli->close();
?>

Example #2 过程化风格

<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}
if ($result = mysqli_query($link, "SELECT * FROM City ORDER BY ID LIMIT 1")) {
    /* determine number of fields in result set */
    $field_cnt = mysqli_num_fields($result);
    printf("Result set has %d fields.\n", $field_cnt);
    /* close result set */
    mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>

以上例程会输出：

Result set has 5 fields.

参见

mysqli_fetch_field() Returns the next field in the result set