php - 合并顺序日期

Question

我的表中有以下数据

根据 shift_id 我想合并类次日期。

简而言之，我想要以下输出:

**output format : FromDate To ToDate (Shift_id)**

2012-12-01 To 2012-12-02 (2)

2012-12-03 (1)

2012-12-04 (2)

2012-12-18 To 2012-12-20 (1)

2012-12-21 To 2012-12-22 (2)

2012-12-23 To 2012-12-24 (1)

2012-12-25 To 2012-12-30 (2)

我尝试了几件事，但没有成功。任何人请帮助/指导我解决这个问题。

这段代码是我写的

    while($row_shift = mysql_fetch_object($result_shift)) {
    $new_date = $row_shift->shift_date;
    $new_shift = $row_shift->shift_id;
    if($new_shift !== $old_shift) {
        $shift_name = $new_shift;
        $shift_date_1 =  date('D d M',strtotime($new_date))." (".$shift_name.")";               
    } else {
        $shift_name = $old_shift;
        $shift_date_1 =  date('D d M',strtotime($old_date))." (".$shift_name.")";
        $diff = abs(floor( (strtotime($new_date) - strtotime($old_date)) / 3600 / 24));
        if($diff == 1) {                    
            $to_part = ' To ';
            $shift_date_2 = date('D d M',strtotime($new_date))." (".$shift_name.")";

        } else {
            $to_part = ' To ';
            $shift_date_2 = date('D d M',strtotime($old_date))." (".$shift_name.")";    
        }
    }

    $s_d_2 = $to_part.$shift_date_2;

    $shift_date[] = $shift_date_1.$s_d_2;

    $old_date = $row_shift->shift_date;
    $old_shift = $row_shift->shift_id;

}
echo implode("<br/>", $shift_date);

这段代码的输出是

Output : 
Sat 01 Dec (2)
Sat 01 Dec (2) To Sun 02 Dec (2)
Mon 03 Dec (1)Sun 02 Dec (2)
Tue 04 Dec (2)Sun 02 Dec (2)
Tue 18 Dec (1)Sun 02 Dec (2)
Tue 18 Dec (1) To Wed 19 Dec (1)
Wed 19 Dec (1) To Thu 20 Dec (1)
Fri 21 Dec (2)Thu 20 Dec (1)
Fri 21 Dec (2) To Sat 22 Dec (2)
Sun 23 Dec (1)Sat 22 Dec (2)
Sun 23 Dec (1) To Mon 24 Dec (1)
Tue 25 Dec (2)Mon 24 Dec (1)
Tue 25 Dec (2) To Wed 26 Dec (2)
Wed 26 Dec (2) To Thu 27 Dec (2)
Thu 27 Dec (2) To Fri 28 Dec (2)
Fri 28 Dec (2) To Sat 29 Dec (2)
Sat 29 Dec (2) To Sun 30 Dec (2)

谢谢。

Answer 1

这是一个SQLFiddle demo

select min(shift_date) start_data,max(shift_date) end_date,
          min(Shift_id) Shift_id
from
(
select t.*,if(shift_id<>@CurShift,@i:=@i+1,@i) Group_num,
       @CurShift:=shift_id 
from t, (select @CurShift:=0,@i:=0) t1 
order by shift_date
 ) b

group by Group_num
order by Group_num