PHP For Loop, Compare Incrementing Value to Incrementing Array - php

Question

Short question: I am trying to see if a variable ($y) is between multiple array values from a database ($ending[0] && $starting[0], $ending[1] && $starting[1], etc...). "If" $y is between any of those, echo "statement".
I'm using a for loop to increment a drop down in 30 minute intervals from 9am - 7pm.
If any of those times = a time saved within my database, it echoes "not available" instead.
Now I need to see "if" the dropdown time is "between" the start and end times in the database and make those "not available" as well.
Everything works if I manually identify which array keys to compare...but my question is: can I check the drop down value against all of the values in the arrays?
Example:
Start Dropdown: 09:00am 09:30am 10:00am etc up until 07:30pm. End Dropdown: 09:30am 10:00am 10:30am etc. up until 08:00pm. If there is a start and end time of 09:00am(start) 10:00am(end) saved in the database for an appointment, the dropdown will show "Not available" for the corresponding starting and end times, so a user cannot double book an appointment. What I am asking about, is how to identify all of the "in between" values...09:30am for example, cannot be a start or an end time, if the 09:00am-10:00am slot is already booked.
$sql_slots = "SELECT * FROM XXXXX WHERE date = '$query_date' ORDER BY XXXXX ASC";
$result_slots = mysqli_query($connection, $sql_slots);
$open = strtotime("9:00am");
$close = strtotime("9:30am");
$starting = array();
$ending = array();
while($row_result_slots = mysqli_fetch_assoc($result_slots)){
$starting[] = $row_result_slots['start_time'];
$ending[] = $row_result_slots['end_time'];
}
echo'
<select name="start_time">';
for($b = 0; $b <= 20; $b++){
$y = strtotime(($b*30) . " Minutes", $open);
$the_time = date("h:ia", $y);
// Here, instead of only comparing the first values in the array, I need to match it up against $ending[1] & $starting[1], $ending[2] & $starting[2], etc...
if(in_array($the_time, $starting) || ($y <= strtotime($ending[0]) && $y >= strtotime($starting[0]))){
echo "<option>Not Available<br></option>";
} else {
echo "<option>" . $the_time . "<br></option>";
}
}
echo'</select>';

Answer 1

How about that?
$sql_slots = "SELECT * FROM XXXXX WHERE date = '$query_date' ORDER BY XXXXX ASC";
$result_slots = mysqli_query($connection, $sql_slots);
$open = strtotime("9:00am");
$close = strtotime("9:30am");
$reserved = array();
while($row_result_slots = mysqli_fetch_assoc($result_slots)){
$start = $row_result_slots['start_time'];
while ($start <= $row_result_slots['end_time']) {
$reserved[$start] = true;
$start = date("Y/m/d h:i:s", strtotime($start . "+30 minutes"));
}
}
echo '<select name="start_time">';
for($b = 0; $b <= 20; $b++){
$y = strtotime(($b*30) . " Minutes", $open);
$the_time = date("h:ia", $y);
if(isset($reserved[$the_time]){
echo "<option>Not Available<br></option>";
} else {
echo "<option>" . $the_time . "<br></option>";
}
}
echo'</select>';

Answer 2

Below is what I came up with. This uses a do while loop and creates a reserved array that will fill all time between what is given in the appointment.
I updated the data to use my own array but updated your mysqli work with what should be correct. If not I left in my testing code for you to view if needed. I also used the disabled attribute on an option over outputting some text.
<?php
$sql_slots = "SELECT * FROM XXXXX WHERE date = '$query_date' ORDER BY XXXXX ASC";
$result_slots = mysqli_query($connection, $sql_slots);
$open = strtotime("9:00am");
$close = strtotime("7:00pm");
$space = 900; //15min * 60 seconds space between?
//This seems more normal for people to see.
//Simulate these appoinments
/*
$query_results = array(
array(
"start_time" => "9:00am",
"end_time" => "9:30am"
),
array(
"start_time" => "10:30am",
"end_time" => "11:30am"
),
array(
"start_time" => "11:45am",
"end_time" => "12:30pm"
)
);
*/
$reserved = array();
while($row_result_slots = mysqli_fetch_assoc($result_slots)){
//**NOTE**: Make sure these are times or use strtotime()
$next_slot = $reserved[] = strtotime($row_result_slots['start_time']);
$end_time = strtotime($row_result_slots['end_time']);
while($next_slot < $end_time){
$next_slot += $space;
$reserved[] = $next_slot;
}
}
/*
foreach($query_results as $appoinment) {
$next_slot = $reserved[] = strtotime($appoinment['start_time']);
$end_time = strtotime($appoinment['end_time']);
while($next_slot < $end_time){
$next_slot += $space;
$reserved[] = $next_slot;
}
}
*/
echo'<select name="start_time">';
$current = $open;
do {
$disabled = in_array($current, $reserved) ? 'disabled' : '';
echo '<option ' . $disabled . '>' . date("h:ia", $current) . '</option>';
$current += $space;
} while($current <= $close);
echo'</select>';