如何在php中验证用户名和密码？

I am using the below php code to fetch the data from the DB. I am unable to check if the Username matches with the entered password.

When correct Username and wrong password is entered, the app gets force closed.

Php code -

<?php

include 'DBConfig.php';

$con = mysqli_connect($HostName,$HostUser,$HostPass,$DatabaseName);

$json = file_get_contents('php://input');

$obj = json_decode($json,true);

$email = $obj['email'];

$password = $obj['password'];

$Sql_Query = "select * from UserRegistrationTable where email = '$email' and password = '$password'; ";

$connection_part = mysqli_query($con,$Sql_Query);
$dataExist=0;

if(mysqli_num_rows($connection_part)>0){ 

 $SuccessLoginMsg = 'Data Matched';

 $SuccessLoginJson = json_encode($SuccessLoginMsg);

echo $SuccessLoginJson ; 

$check = mysqli_fetch_array($connection_part);

$response=array();
array_push($response,array("name"=>$check[1], "email"=>$check[2], "password"=>$check[3]);

echo json_encode(array("Details"=>$response));     
}

 else{

$InvalidMSG = 'Invalid Username or Password Please Try Again' ;

$InvalidMSGJSon = json_encode($InvalidMSG);

echo $InvalidMSGJSon ;

 }

 mysqli_close($con);
?>

You should switch your if statements or better change the '>' to '<'. if there are rows in your sql query means the username and password matches. You have it the other way around hope this helps.