Have old php web how change mssql to sqlsrv all

Question

    $host = "MyIP"; 
    $alogin = "user";  
    $apass = "password";  
    $db = "mydatabase";  
    $msconnect=mssql_connect("$host","$alogin","$apass");
    $msdb=mssql_select_db("$db",$msconnect);

I tried to change, I think it works, but it's very slow loading:

    $connectionInfo = array( "Database"=>"host", "UID"=>"alogin", "PWD"=>"apass");
    $conn = sqlsrv_connect( $db, $connectionInfo);

mssql_query and result - how to change those? //Character - My database Table

I get a fatal error:

Uncaught Error: Call to undefined function mssql_query()

    $echo = mssql_query("SELECT count(*) FROM Character");
    echo mssql_result($echo, 0, 0);

Fixed login database loading, normal time.Login database work perfect.

    $host = "MyIP"; 
    $alogin = "user";  
    $apass = "password";  
    $db = "mydatabase";
    $conn = new PDO("sqlsrv:server=$host;Database=$db",$alogin,$apass,);

Changed mssql_query , mssql_result to:

    $query = 'select count (*) from Character';
    $stmt = $conn->query( $query );

while ($row = $stmt->fetch(PDO::FETCH_ASSOC)){
    print_r($row);
};

I get code ansver Array ( [] => 74 ), code work good (My character yes 74) but how delete Array ( [] => )