（更新设置）您的SQL语法中有错误

This code works, table is updating, but server responds: "You have an error in your SQL syntax".

Asking for the sake of interest. Please tell me where is an error

$id = $_POST['id'];
$name = $_POST['name'];
$image = $_POST['image'];
$price = $_POST['price'];

mysql_connect("localhost","main","password");
mysql_select_db("main");

$result = mysql_query("SELECT * FROM goods WHERE id='".$id."'");
if(mysql_num_rows($result) > 0) {
    $newquery = mysql_query("UPDATE goods SET name='".$name."', image='".$image."', price='".$price."' WHERE id='".$id."'");
    if(!mysql_query($newquery)) {
        die('Invalid query: ' . mysql_error());
    } else {
        echo "Updated successfully";
        }
    } else {
        echo "Error: there is no such product in DB";
    }

Error:

Invalid query: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '1' at line 1

Your where condition is wrong. It is expecting an integer not a string for ID.

Should be:

$newquery = mysql_query("UPDATE goods SET name='".$name."', image='".$image."', price='".$price."' WHERE id=".$id);

But you should note 2 things.

1. mysql_query and all mysql_ functions have been replaced by mysqli_

2. you are vulnerable to SQL injection. You should use PDO or any ORM/Database Abstraction to handle queries for you to prevent that.

'name' is a MySQL keyword. If you plan to use it as a column name then you must use back ticks when performing queries on the column:

"UPDATE `goods` SET `name`='".$name."', `image`='".$image."', `price`='".$price."' WHERE `id`='".$id."'"

Your insert values are strings. So you have to use " or ' to wrap it:

$sql = "UPDATE users SET fullname = '".$fullname."', bio = '".$bio."', 
birthdate = '".$birthdate."', pass = '".$newpass."',
WHERE username = '".$susername."'";