How to check if MySQL results returned empty in PH

Question

How to check mysql results are empty or not. if mysql query results are empty then else condtion should not be excueted. In case mysql results data there & in else condition my error my message are there but it is not showing any error message. I have tried following code but not showing any alert or echo message on screen.

<?php
$sql = "select * from hall_search_data_1 where rent BETWEEN '".$_SESSION['amount1']."' AND '".$_SESSION['amount2']."'";
$res = mysql_query($sql);
if(!empty($res)){
while($row=mysql_fetch_row($res))
{
// here my data 
}
}else{
echo "no results found";
echo "<br>";
echo "<script>alert('No any result found..!!');</script>";
echo "no results found";
}
?>

Answer 1

you can just replace if(!empty($res)) with mysql_num_rows like this -

$sql = "select * from hall_search_data_1 where rent BETWEEN '".$_SESSION['amount1']."' AND '".$_SESSION['amount2']."'";
$res = mysql_query($sql);
if($countrows = mysql_num_rows($res) >= 1){
    while($row=mysql_fetch_row($res))
    {
        here my data 
    }
}else{
    echo "no results found";
    echo "<br>";
    echo "<script>alert('No any result found..!!');</script>";
    echo "no results found";
}