mysql查询日期补全（连续）方法

SELECT    od.date,    od.orderCountFROM    (        SELECT            DATE_FORMAT(order_time,'%Y-%m-%d') date,            count(*) orderCount        FROM            order        WHERE            order_time>'开始时间' and order_time<'结束时间'        GROUP BY DATE_FORMAT(order_time,'%Y-%m-%d')        UNION (SELECT 0, '2017-03-01')        UNION (SELECT 0, '2017-03-02')        UNION (SELECT 0, '2017-03-03')        UNION (SELECT 0, '2017-03-04')        UNION (SELECT 0, '2017-03-05')        UNION (SELECT 0, '2017-03-06')        UNION (SELECT 0, '2017-03-07')        UNION (SELECT 0, '2017-03-08')        -- 很多个UNION ......    ) AS odGROUP BY od.dateORDER BY od.date ASC如果有日期表那就用联表就行了，这里是不联表的方法，在程序上做处理后拼接到sql上 
public function getLaidianLaifang($proj_ids, $start_date, $end_date, $gjfs, $type){    if(empty($proj_ids)){        return [];    }    $where = " and proj_id in ('".implode("','", $proj_ids)."')";    $rs = $this->dealDate($type, $start_date, $end_date);    $group = $rs['group'];    $union = $rs['union'];    $sql = "select d.gj_cst_sum,d.date_type from (select count(DISTINCT opp_id) as gj_cst_sum,{$group} as date_type from s_opp2gjjl where gjfs = {$gjfs} and gj_date BETWEEN :start_date and :end_date {$where} GROUP BY {$group} {$union})             as d GROUP BY d.date_type ORDER BY d.date_type ASC";    return $this->kfsDb->createCommand($sql, [':start_date' => $start_date, ':end_date' => $end_date.' 23:59:59'])->queryAll();}

/** * 处理时间，把缺的补上 * */private function dealDate($type, $start_date, $end_date, $proj = null){    $union = '';    $group = '';    if($type == 1){        $group = "HOUR(gj_date)";        for($i = 0; $i < 24; $i++){            $union .= " UNION (SELECT 0,{$i} {$proj})";        }    }elseif($type == 3){        $group = "DATE(gj_date)";        for($i = $start_date; $i <= $end_date; $i++){            $union .= " UNION (SELECT 0, '{$i}' {$proj})";        }    }elseif ($type == 4){        $group = "WEEK(gj_date,0)";        $s = date('W',strtotime($start_date));        $e = date('W',strtotime($end_date));        for($i = $s; $i <= $e; $i++){            $union .= " UNION (SELECT 0,{$i} {$proj})";        }    }elseif ($type == 5){        $group = "MONTH(gj_date)";        $s = date('n',strtotime($start_date));        $e = date('n',strtotime($end_date));        for($i = $s; $i <= $e; $i++){            $union .= " UNION (SELECT 0,{$i} {$proj})";        }    }    return ['group' => $group, 'union' => $union];}