选择行到列的某种方法-SQL Server

我想知道是否有办法选择下面的表格

ID | DOCNo | Date

1  | 20    | 12-DEC-12
2  | 21    | 02-NOV-12
3  | 20    | 18-JAN-13
4  | 20    | 10-APR-13
5  | 22    | 12-DEC-12

要在SQL SERVER 2008中执行类似操作，请执行以下操作：

DOCNo | ID1 | Date1     | ID2  | Date2     | ID3  | Date3 

20    |  1  | 12-DEC-12 |  3   | 18-JAN-13 |  4   | 10-APR-13  
21    |  2  | 02-NOV-12 | NULL |   NULL    | NULL |   NULL    
22    |  5  | 12-DEC-12 | NULL |   NULL    | NULL |   NULL  

*DOCNo在表中的记录永远不会超过3条

我正在使用SQLServer2008

谢谢

MS SQL Server 2008架构设置：

问题1：

---

获得最终结果的一种简单方法是使用row_number为每个docno生成一个序列，然后使用CASE表达式应用聚合函数：

select docno,
  max(case when seq = 1 then id end) id1,
  max(case when seq = 1 then date end) date1,
  max(case when seq = 2 then id end) id2,
  max(case when seq = 2 then date end) date2,
  max(case when seq = 3 then id end) id3,
  max(case when seq = 3 then date end) date3
from
(
  select id, docno, date,
    row_number() over(partition by docno order by date) seq
  from yourtable
) d
group by docno;

---

请参见选择表中是否有有限数量的IDn。意思是ID1，ID2，ID3是它停止的地方，或者它在内部。你能有7，10，15…实际上我刚刚看到：DOCNo在表中的记录永远不会超过3条。。。。它必须是一个查询还是一个存储过程。。。。我能想到一种使用临时表的方法。嗨，物流学家，谢谢你的回复。。。你认为有可能是一个问题吗？这是我最好的选择。。。

SELECT r1.DOCNo, 
       r1.ID as ID1, r1.Date as Date1,
       r2.ID as ID2, r2.Date as Date2,
       r3.ID as ID3, r3.Date as Date3
FROM Table1 r1
LEFT OUTER JOIN Table1 r2 ON r1.DOCNo = r2.DOCNo AND r1.ID < r2.ID
LEFT OUTER JOIN Table1 r3 ON r1.DOCNo = r3.DOCNo AND r1.ID < r3.ID 
                                                 AND r2.ID < r3.ID
WHERE r1.ID = (SELECT min(ID) 
                 FROM Table1 
                WHERE DOCNo = r1.DOCNo 
                GROUP BY DOCNo)
AND (CASE WHEN (SELECT count(*) 
                  FROM Table1 
                 WHERE DOCNo = r1.DOCNo 
                 GROUP BY DOCNo) = 2 THEN r2.ID
          WHEN (SELECT count(*) 
                  FROM Table1 
                 WHERE DOCNo = r1.DOCNo 
                 GROUP BY DOCNo) = 3 THEN r3.ID ELSE 1 END) IS NOT NULL

| DOCNO | ID1 |     DATE1 |    ID2 |     DATE2 |    ID3 |     DATE3 |
|-------|-----|-----------|--------|-----------|--------|-----------|
|    20 |   1 | 12-DEC-12 |      3 | 18-JAN-13 |      4 | 10-APR-13 |
|    21 |   2 | 02-NOV-12 | (null) |    (null) | (null) |    (null) |
|    22 |   5 | 12-DEC-12 | (null) |    (null) | (null) |    (null) |
|    23 |   6 | 21-JAN-13 |      7 | 24-FEB-13 | (null) |    (null) |

select docno,
  max(case when seq = 1 then id end) id1,
  max(case when seq = 1 then date end) date1,
  max(case when seq = 2 then id end) id2,
  max(case when seq = 2 then date end) date2,
  max(case when seq = 3 then id end) id3,
  max(case when seq = 3 then date end) date3
from
(
  select id, docno, date,
    row_number() over(partition by docno order by date) seq
  from yourtable
) d
group by docno;