php - 解析错误：语法错误，第 9 行 C:\wamp\www\insert_data.php 中的意外 '='

Question

所以我得到了这个错误：

Parse error: syntax error, unexpected '=' in C:\wamp\www\insert_data.php on line 9

在这条线上：

$std-id = $_POST['std_id'];

我的PHP代码是：

<?php

if ( isset($_POST['submitted'] ) )
{
include ('mysql_connect.php') ;

$std-id = $_POST['std_id'];
$std-name = $_POST['std_name'];
$std-year = $_POST['year'];
$std-degree = $_POST['degree'];

$sqlinsert = "INSERT INTO student ( ID , Name , Year ,  Degree ) VALUES (' $std-id ' ,   ' $std-name ' , ' $std-year ' , ' $std-degree ' ) ";

if (!mysql_query ( $dbcon, $sqlinsert ) ) {
die( ' error inserting new record ' ) ;
} // end of nested if statment

$newrecord = " 1 record added to the database " ;
} // end of the main if statement

?>

Answer 1

变量名中不能有破折号。从手册：

有效的变量名称以字母或下划线开头，后跟任意数量的字母、数字或下划线。