ConFoo 2025

mysqli::$field_count

mysqli_field_count

(PHP 5, PHP 7, PHP 8)

mysqli::$field_count -- mysqli_field_countReturns the number of columns for the most recent query

说明

面向对象风格

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()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) {
/* this was a select/show or describe query */
$result = $mysqli->store_result();

/* process resultset */
$row = $result->fetch_row();

/* free resultset */
$result->close();
}

/* close connection */
$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)) {
/* this was a select/show or describe query */
$result = mysqli_store_result($link);

/* process resultset */
$row = mysqli_fetch_row($result);

/* free resultset */
mysqli_free_result($result);
}

/* close connection */
mysqli_close($link);
?>
添加备注

用户贡献的备注

此页面尚无用户贡献的备注。
To Top