php 获取时间段

       switch ($type){
            case 'day'://当日
                $end=date('Y-m-d H:i:s',mktime(0,0,0,date('m'),date('d')+1,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(0,0,0,date('m'),date('d')-6,date('Y')));
                $week_end=date('Y-m-d H:i:s',mktime(0,0,0,date('m'),date('d')+1,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
                $getWeekDay=date("w");
                $week_now_start= date("Y-m-d 00:00:00",mktime(0,0,0,date("m"),date("d")-$getWeekDay+1-7,date("Y")));
                $week_now_end= date("Y-m-d 23:59:59",mktime(0,0,0,date("m"),date("d")-$getWeekDay+7-7,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(0,0,0,date('m'),date('d')-29,date('Y')));
                $month_end=date('Y-m-d H:i:s',mktime(0,0,0,date('m'),date('d')+1,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(0,0,0,date('m'),1,date('Y')));
                $month_now_end=date('Y-m-d H:i:s',mktime(23,59,59,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'))/3);//当月是第几季度
                $quarter_now_start=date('Y-m-d H:i:s',mktime(0, 0, 0,$season*3-3+1,1,date('Y')));
                $quarter_now_end=date('Y-m-d H:i:s',mktime(23,59,59,$season*3,date('t',mktime(0, 0 , 0,$season*3,1,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 H:i:s',mktime(0,0,0,date('m'),date('d')+1,date('Y')));
                $where='and '.$pre.'create_time<="'.$all_end.'"';
                break;
        }