php论坛登录抛出错误[重复]

Question

This question already has an answer here:

• Warning: mysqli_query() expects parameter 1 to be mysqli, null given in 3 answers

Ive tried my best to try and fix this multiple time but something is still wrong with the code and I keep getting errors coming from the php

Warning: mysqli_query() expects parameter 1 to be mysqli, null given in /home/a9114464/public_html/api/api.php on line 10
Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, null given in /home/a9114464/public_html/api/api.php on line 12

Now here is the api.php file

$conn = mysqli_connect("EXAMPLE", "EXAMPLE", "EXAMPLE");

if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

function login($username, $password){
$sql = "SELECT * from users WHERE username='$username' AND password='$password'";
$result = mysqli_query($conn, $sql);

$check_user = mysqli_num_rows($result);
if($check_user>0){

$_SESSION[‘username’]=$username;

}

}

Thanks in advance :)

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Answer 1

Solution:

Warning: mysqli_query() expects parameter 1 to be mysqli, null given in /home/a9114464/public_html/api/api.php on line 10

--> $conn is defined and assigned outside function. Use global to get use $conn in the function scope.

function login($username, $password){
 global $scope;

OR, pass $conn as third parameter to login. And call login() with three parameters.

function login($username, $password, $conn) {

Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, null given in /home/a9114464/public_html/api/api.php on line 12

--> When first problem fixed, this will also be fixed.