<?php
//database settings
$hostname="localhost";
$database="alex";
$username="root";
$password="";
$mysqli = new mysqli($hostname,$username,$password,$database);

//query
$query = "SELECT `useerName FROM `users`";
$result = $mysqli->query($query);

//process result
$result_array=array();
while($row = $Result->fetch_assoc())
{
    $Result_Array[] = $row;
}
?>

Hope the below code helps:

<?php

$servername = "localhost";
$username = "your username";
$password = "your password";
$dbname = "your dbname";

// Create connection
$conn = mysqli_connect($servername, $username, $password, $dbname);
// Check connection
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}
$getname= $_POST['name'];
$sql = "SELECT userName FROM users WHERE userName LIKE '%$getname%';
$result = mysqli_query($conn, $sql);

if ($result->num_rows > 0) {
     echo "<table><tr><th>Name</th></tr>";
     // output data of each row
     while($row = $result->fetch_assoc()) {
         echo "<tr><td>" . $row["userName"]. "</td></tr>";
     }
     echo "</table>";
} else {
    echo "0 results";
}

mysqli_close($conn);
?>