$countries = [
'Africa' => [ "Mammuthus columbi",
"African buffalo",
"Bongo",
"Giraffe",
"Zebra"],
'Australia' => [ "Australian echidna",
"Asian buffalo",
"Camel",
"Dingo",
"Kangaroo"],
];
foreach ($countries as $country => $cities) {
echo '<h2>'.$country.'</h2><br/>'.implode(',<br/>', $cities).'.<br/>';
}
SELECT CONCAT(`h`.`hour`, ':', `m`.`minute`, ':00')
FROM (
SELECT '09' AS `hour`
UNION SELECT '10'
UNION SELECT '11'
UNION SELECT '12'
UNION SELECT '13'
UNION SELECT '14'
UNION SELECT '15'
UNION SELECT '16'
UNION SELECT '17'
) AS `h`
JOIN (
SELECT '00' AS `minute`
UNION SELECT '15'
UNION SELECT '30'
UNION SELECT '45'
) AS `m`