PHP mysqli_stmt $field_count 属性

 PHP MySQLi 函数

PHP mysqli_stmt::$field_count / mysqli_stmt_field_count() 函数返回准备好的语句中的列数。

语法

//面向对象风格
$mysqli_stmt->field_count;

//面向过程风格
mysqli_stmt_field_count(statement)

参数

返回值

返回整数表示列数。

示例:面向对象风格

下面的示例显示了 mysqli_stmt::$field_count 属性的用法。

<?php
//建立与数据库的连接
$mysqli = new mysqli("localhost", "user", "password", "database");
if ($mysqli->connect_errno) {
  echo "Failed to connect to MySQL: ". $mysqli->connect_error;
  exit();
}

//准备执行SQL语句
$query = "SELECT EmpID, Name, Age FROM Employee ORDER BY Age";
$stmt = $mysqli->prepare($query);

//执行SQL语句
$stmt->execute();

//将结果存储在内部缓冲区中
$stmt->store_result();

//获取准备好的语句中的字段数
$field_cnt = $stmt->field_count;

printf("Statement has %d fields.\n", $field_cnt);
?>

上述代码的输出将是:

Statement has 3 fields.

示例:面向过程风格

下面的示例显示mysqli_stmt_field_count() 的用法 函数。

<?php
//建立与数据库的连接
$mysqli = mysqli_connect("localhost", "user", "password", "database");
if (mysqli_connect_errno()) {
  echo "Failed to connect to MySQL: ". mysqli_connect_error();
  exit();
}

//准备执行SQL语句
$query = "SELECT EmpID, Name, City FROM Employee ORDER BY Age";
$stmt = mysqli_prepare($mysqli, $query);

//执行SQL语句
mysqli_stmt_execute($stmt);

//将结果存储在内部缓冲区中
mysqli_stmt_store_result($stmt);

//获取准备好的语句中的字段数
$field_cnt = mysqli_stmt_field_count($stmt);

printf("Statement has %d fields.\n", $field_cnt);
?>

上述代码的输出将是:

Statement has 3 fields.