$tmp = array('a','b','c','d','e','f','g','h'); pat($tmp); function pat($arr,$level=0,$base = ""){ $num = count($arr); if($num == 0){ print $base."\n"; } for($i = 0;$i if(isset($arr[$i])){ $arrclone = $arr; unset($arrclone[$i]); pat($arrclo…

SELECT datname FROM pg_database ;