Booking Availability - php

Question

I have a database field which are
Appt_Datetime (which is call as DateTime in my table)
Svc_ID (which i call ApptType in my table)
I wanted the system to let the customer know that the datetime for the appt type is not available once someone else has book that slot.I have done a lot of research and trying out different codes but to no avail. I've seen answers on stackoverflow that uses PDO but im not so clear about it hence i'd like something to do with mysql. I have been stuck at with this at least few weeks now. Help
This is my call func:
$datetime = $_POST['DateTime'];
$appt = $_POST['ApptType'];
This is the query i last tried out but still is not working:
//Define query
$vquery = "SELECT * FROM Appointment where Appt_DateTime='$datetime' && Svc_ID='$appt'";
//Run Query
$result = mysql_query($query, $conn);
$row = mysql_fetch_assoc($result);
if($row==1)
{
echo "Date in not available";
}
else if($row==0)
{
$query = "INSERT INTO Appointment (Client_ID,Svc_ID,Appt_DateTime)
VALUES ('$_POST[ClientID]','$_POST[ApptType]','".date('Y-m-d H:i:s', strtotime($_POST[DateTime]))."')";
mysql_query($query,$conn);
}

Answer 1

Hint:
change this to $result = mysql_query($query, $conn); to $result = mysql_query($vquery, $conn);

Answer 2

at the time you are using $conn you do not have $query it is $vquery:
$result = mysql_query($vquery, $conn);
And as suggested above in comments better use mysqli or PDO.

Answer 3

you can try this condition..
//Define query
$vquery = "SELECT * FROM Appointment where Appt_DateTime='$datetime' && Svc_ID='$appt'";
//Run Query
if($result = mysql_query($vquery, $conn)){
//$row = mysql_fetch_assoc($result);
if(mysql_num_row($result)>0)
{
echo "Date in not available";
}
else
{
/* $query = "INSERT INTO Appointment (Client_ID,Svc_ID,Appt_DateTime)
VALUES ('$_POST[ClientID]','$_POST[ApptType]','".date('Y-m-d H:i:s', strtotime($_POST[DateTime]))."')";
mysql_query($query,$conn); */
echo "insert";
}
}else{
echo mysql_error();
}