php mysqli语法错误

Question

我的代码出了什么问题？我确定$_POST['item']具有有效值

<?php

$data = $_POST['item'];

$conn = mysqli_connect("localhost","root","");
mysqli_select_db($conn, "ajaxexample");

$q = INSERT INTO user (userList) VALUES ('$data');
if(mysqli_query($conn, $q)){

echo 1;

}

?>

Answer 1

将INSERT INTO user (userList) VALUES ('$data');放在双引号中。

例如：

$q = "INSERT INTO user (userList) VALUES ('$data')";

Answer 2

PHP字符串文字必须在引号中。

要通过仅更改一行来解决此问题：

$q = "INSERT INTO user (userList) VALUES ('" . mysqli_real_escape_string($data . "')";

Answer 3

<?php

$data = $_POST['item'];

$conn = mysqli_connect("localhost","root","", "ajaxexample");

$q = INSERT INTO user (userList) VALUES ('$data');
if(mysqli_query($conn, $q)){

echo 1;

}

?>

Not mysqli_select_db