高效地將列轉置爲行

您可以幫助我完成此項目嗎？我研究了以前提出的問題，但他們似乎沒有解決這種獨特的情況。高效地將列轉置爲行

的樣本數據：

Member | DOS | Dx1 | Dx2 | Dx3 | Dx4 | Dx5 
12345 | 1/1/2011 | 12142 | 12345 | 65657 | 5657 | 568 
56484 | 3/5/2011 | 568 | 56785 | 5695 | 575 | 168 
56872 | 2/12/2011 | 567 | 567 |

我需要看到的是這樣的：

Member DOS DX Seq 
12345 1/1/2011 12142 Dx1 
12345 1/1/2011 12345 Dx2 
12345 1/1/2011 65657 Dx3

等等。只顯示那些不是零的Dx - 所以對於56872，我們只會看到Dx1和Dx2，但對於其他2，我們會看到所有5個Dx的記錄。

有人能幫我嗎？謝謝。

來源

2013-12-22 user3127999

這並沒有表現得很好。我的數據很流行，其中Dx1，Dx2等是列 - 我需要它們是行，Seq告訴我它是哪個Dx＃。謝謝。 – user3127999

@TastySpaceApple：爲什麼mongodb標籤？ –

那麼這3個monngo文件是你想要轉換的，在這種情況下，12？正在使用任何特定的語言？或者它是mongo控制檯？ – xcorat

這種類型的數據轉換稱爲UNPIVOT。不幸的是，MySQL不具有unpivot功能，但您可以通過幾種不同的方式複製功能。

您可以使用UNION ALL查詢到每個列的值轉換成行：

select member, dos, dx, seq 
from 
(
    select member, dos, dx1 as dx, 'Dx1' as seq 
    from yourtable 
    union all 
    select member, dos, dx2 as dx, 'Dx2' as seq 
    from yourtable 
    union all 
    select member, dos, dx3 as dx, 'Dx3' as seq 
    from yourtable 
    union all 
    select member, dos, dx4 as dx, 'Dx4' as seq 
    from yourtable 
    union all 
    select member, dos, dx5 as dx, 'Dx5' as seq 
    from yourtable 
) d 
where dx is not null 
order by member, seq;

見SQL Fiddle with Demo。這種方法會得到結果，但在大型表上可能效率不高。

另一種方法是使用交叉上的虛擬表JOIN：

select member, dos, dx, seq 
from 
(
    select t.member, t.dos, 
    case s.seq 
     when 'Dx1' then dx1 
     when 'Dx2' then dx2 
     when 'Dx3' then dx3 
     when 'Dx4' then dx4 
     when 'Dx5' then dx5 
    end DX, 
    s.seq 
    from yourtable t 
    cross join 
    (
    select 'Dx1' as seq union all 
    select 'Dx2' as seq union all 
    select 'Dx3' as seq union all 
    select 'Dx4' as seq union all 
    select 'Dx5' as seq 
) s 
) d 
where dx is not null 
order by member, seq;

參見SQL Fiddle with Demo。兩者都給出了結果：

| MEMBER |        DOS | DX | SEQ | 
|--------|---------------------------------|-------|-----| 
| 12345 | January, 01 2011 00:00:00+0000 | 12142 | Dx1 | 
| 12345 | January, 01 2011 00:00:00+0000 | 12345 | Dx2 | 
| 12345 | January, 01 2011 00:00:00+0000 | 65657 | Dx3 | 
| 12345 | January, 01 2011 00:00:00+0000 | 5657 | Dx4 | 
| 12345 | January, 01 2011 00:00:00+0000 | 568 | Dx5 |

來源

2014-01-02 13:52:10 Taryn

高效地將列轉置爲行

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