php 获取时间段

switch ($type){
    case 'day'://当日
        $end=date('Y-m-d H:i:s',mktime(,,,date('m'),date('d')+,date('Y')));
        $where=' and '.$pre.'create_time>="'.date('Y-m-d').'" and '.$pre.'create_time<="'.$end.'"';
        break;
    case 'week'://获取周数据:往前推6天
        $week_start=date('Y-m-d H:i:s',mktime(,,,date('m'),date('d')-,date('Y')));
        $week_end=date('Y-m-d H:i:s',mktime(,,,date('m'),date('d')+,date('Y')));
        $where='and '.$pre.'create_time>="'.$week_start.'" and '.$pre.'create_time<="'.$week_end.'"';
        break;
    case 'week_now'://获取本周数据
        $week_now_start=date("Y-m-d H:i:s",mktime(,  , ,date("m"),date("d")-date("w")+,date("Y")));
        $week_now_end=date("Y-m-d H:i:s",mktime(,,,date("m"),date("d")-date("w")+,date("Y")));
        $where='and '.$pre.'create_time>="'.$week_now_start.'" and '.$pre.'create_time<="'.$week_now_end.'"';
        break;
    case 'month'://获取月数据:往前推30天
        $month_start=date('Y-m-d H:i:s',mktime(,,,date('m'),date('d')-,date('Y')));
        $month_end=date('Y-m-d H:i:s',mktime(,,,date('m'),date('d')+,date('Y')));
        $where='and '.$pre.'create_time>="'.$month_start.'" and '.$pre.'create_time<="'.$month_end.'"';
        break;
    case 'month_now'://获取本月数据
        $month_now_start=date('Y-m-d H:i:s',mktime(,,,date('m'),,date('Y')));
        $month_now_end=date('Y-m-d H:i:s',mktime(,,,date('m'),date('t'),date('Y')));
        $where='and '.$pre.'create_time>="'.$month_now_start.'" and '.$pre.'create_time<="'.$month_now_end.'"';
        break;
    case 'quarter_now'://获取本季度数据
        $season = ceil((date('n'))/);//当月是第几季度
        $quarter_now_start=date('Y-m-d H:i:s',mktime(, , ,$season*-+,,date('Y')));
        $quarter_now_end=date('Y-m-d H:i:s',mktime(,,,$season*,date('t',mktime(,  , ,$season*,,date("Y"))),date('Y')));
        $where='and '.$pre.'create_time>="'.$quarter_now_start.'" and '.$pre.'create_time<="'.$quarter_now_end.'"';
        break;
    case 'year_now'://获取本年数据
        $year_now_start=date('Y-01-01 00:00:00',time());
        $year_now_end=date('Y-12-31 23:59:59',time());
        $where='and '.$pre.'create_time>="'.$year_now_start.'" and '.$pre.'create_time<="'.$year_now_end.'"';
        break;
    case 'all'://获取今天之前的数据
        $all_end=date('Y-m-d 23:59:59',mktime(,,,date('m'),date('d'),date('Y')));
        $where='and '.$pre.'create_time<="'.$all_end.'"';
        break;
}