PHP For Loop, Compare Incrementing Value to Incrementing Array

• 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?

$sql_slots = "SELECT * FROM XXXXX WHERE date = '$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>';