PHP String Manipulation and SQL Query - php

Question

Hi still a beginner in php programming and one of the function of my project is to check if the schedule exist or not in the database. anyway my problem is that the way i created the string query, i am not sure if the string is correct in terms of syntax but the query is correct and tested in the phpmyadmin MySQL GUI.
$start_time = $_POST['Time-In'];
$end_time = $_POST['Time-Out'];
$procedure_date = $_POST['txbDateofProcedure'];
$DateStartTime = $procedure_date." ".$start_time;
$DateEndTime = $procedure_date." ".$end_time;
//Not sure but i think that the $Check-Schedule php syntax is incorrect
$Check_Schedule = "select * from appointment_dim where dentist_id = '$dentist_id'".
"and (CONCAT(appoint_date, ,appoint_timein) between '$DateStartTime' and '$DateEndTime')".
"OR (CONCAT(appoint_date, ,appoint_timeout) between '$DateStartTime' and '$DateEndTime')";
$result_schedule = mysql_query($Check_Schedule,$con);
if(!$result_schedule)
{
trigger_error("Cannot located database".mysql_error());
die();
}
if(mysql_num_rows($result_schedule) > 0)
{
$SchedErrMesg = "The time you requested is already take try again.";
echo"<script type='text/javascript'>alert('$SchedErrMesg');</script>";
die();
}

Answer 1

if you want the delimiter between appoint_date and appoint_time* to be space, you should do this:
CONCAT(appoint_date, ' ', appoint_timein)
but not this:
CONCAT(appoint_date, , appoint_timein)
Also i believe u want the logic like
"dentist_id = x AND (timeBetween1 OR timeBetween2)"
But not that u wrote:
"(dentist_id = x AND timeBetween1) OR timeBetween2"
So try this:
$Check_Schedule = "
SELECT * FROM appointment_dim
WHERE
dentist_id = '$dentist_id'
AND (
(CONCAT(appoint_date, ' ', appoint_timein) BETWEEN '$DateStartTime' AND '$DateEndTime')
OR (CONCAT(appoint_date, ' ', appoint_timeout) BETWEEN '$DateStartTime' AND '$DateEndTime')
)
";