find zodiac from a SQL like birthday date

zodiac.php

<?php

function zodiac($birthday)
{
	$zodiac = '';
	[$year, $month, $day] = explode ('-', $birthday);
	if     ( ( $month == 3 && $day > 20 ) || ( $month == 4 && $day < 20 ) ) { $zodiac = 'Aries'; }
	elseif ( ( $month == 4 && $day > 19 ) || ( $month == 5 && $day < 21 ) ) { $zodiac = 'Taurus'; }
	elseif ( ( $month == 5 && $day > 20 ) || ( $month == 6 && $day < 21 ) ) { $zodiac = 'Gemini'; }
	elseif ( ( $month == 6 && $day > 20 ) || ( $month == 7 && $day < 23 ) ) { $zodiac = 'Cancer'; }
	elseif ( ( $month == 7 && $day > 22 ) || ( $month == 8 && $day < 23 ) ) { $zodiac = 'Leo'; }
	elseif ( ( $month == 8 && $day > 22 ) || ( $month == 9 && $day < 23 ) ) { $zodiac = 'Virgo'; }
	elseif ( ( $month == 9 && $day > 22 ) || ( $month == 10 && $day < 23 ) ) { $zodiac = 'Libra'; }
	elseif ( ( $month == 10 && $day > 22 ) || ( $month == 11 && $day < 22 ) ) { $zodiac = 'Scorpio'; }
	elseif ( ( $month == 11 && $day > 21 ) || ( $month == 12 && $day < 22 ) ) { $zodiac = 'Sagittarius'; }
	elseif ( ( $month == 12 && $day > 21 ) || ( $month == 1 && $day < 20 ) ) { $zodiac = 'Capricorn'; }
	elseif ( ( $month == 1 && $day > 19 ) || ( $month == 2 && $day < 19 ) ) { $zodiac = 'Aquarius'; }
	elseif ( ( $month == 2 && $day > 18 ) || ( $month == 3 && $day < 21 ) ) { $zodiac = 'Pisces'; }

	return $zodiac;
}