考虑下面基于sql Server的场景(取自http://forums.aspfree.com/microsoft-sql-server-14/merge-the-two-rows-in-one-row-245550.html)

鉴于有一张桌子

EMP

ID |名称|
1 | x |
1 | P |
2 | y |
2 |问|
3 | W |

我们希望select语句中的结果数据输出：

Emp_Data

Id |名字-1 |名字-2 |
1 | x | P |
2 | y |问|
3 | w | |

帖子中的答案表明以下sql是一种可能的解决方案：

SELECT 
   a.ID,[Name-1] = ISNULL(( 
   SELECT TOP 1 Name 
   FROM emp 
   WHERE ID = a.ID),''),[Name-2] = ISNULL(( 
   SELECT TOP 1 b.Name 
   FROM emp b 
   WHERE b.ID = a.ID 
       AND Name NOT IN( 
           SELECT TOP 1 Name 
           FROM emp 
           WHERE ID = b.ID 
       )),'') 
FROM emp a 
GROUP BY a.ID

使用sqlite可以生成列[Name-1]& [Name-2]使用嵌套的SELECT语句,就像我们在sql Server中可以做的那样？

SELECT 
   a.ID,COALESCE(a.Name,'') as "Name-1",COALESCE((SELECT b.Name FROM Emp b 
             WHERE b.ID = a.ID
             AND b.rowid != a.rowid LIMIT 1),'') as "Name-2"
FROM emp a 
GROUP BY a.ID