Divide 24 hours into 3 shifts schedule with MySQL date_format function

$first_shift_time_in = 7;
$first_shift_time_out = 14;
$second_shift_time_in = 15;
$second_shift_time_out = 22;
$third_shift_time_in_a = 23;
$third_shift_time_in_b = 0;
$third_shift_time_in_b = 1;
$third_shift_time_out_b = 6;

<?php
	require ("connection.php");	
	$query = mysql_query("select date_format(now(), '%H') as time") or die (mysql_error());
	while ($row = mysql_fetch_array($query)) {
		$time = $row[time];
	}
	//echo "<br>";
	$first_shift_time_in = 7;
	$first_shift_time_out = 14;
	$second_shift_time_in = 15;
	$second_shift_time_out = 22;
	$third_shift_time_in_a = 23;
	$third_shift_time_in_b = 0;
	$third_shift_time_in_b = 1;
	$third_shift_time_out_b = 6;
 
	for($i = $first_shift_time_in; $i <= $first_shift_time_out; $i++) {
		if($time == $i) {
			$shift = "First Shift";
		}
	}
	for($ii = $second_shift_time_in; $ii <= $second_shift_time_out; $ii++) {
		if($time == $ii) {
			$shift = "Second Shift";
		}
	}
//	echo "<br>";
	for($iii = $third_shift_time_in_b; $iii <= $third_shift_time_out_b; $iii++) {
		if($time == $iii) {
			$shift = "Third Shift";
		}
	}
	if($time == 23) {
		$shift = "Third Shift";
	} 
	if($time == 0) {
		$shift = "Third Shift";
	}
echo "You are: ". $shift;	
?>