sql - 分组和切换列和行

Question

我不知道这是否会被正式称为枢轴，但我想要的结果是这样的:

+------+---------+------+
| Alex | Charley | Liza |
+------+---------+------+
|  213 |     345 |    1 |
|   23 |     111 |    5 |
|   42 |      52 |    2 |
|  323 |         |    5 |
|   23 |         |    1 |
|  324 |         |    5 |
+------+---------+------+

我的输入数据采用以下形式:

+-----+---------+
| Apt |  Name   |
+-----+---------+
| 213 | Alex    |
|  23 | Alex    |
|  42 | Alex    |
| 323 | Alex    |
|  23 | Alex    |
| 324 | Alex    |
| 345 | Charley |
| 111 | Charley |
|  52 | Charley |
|   1 | Liza    |
|   5 | Liza    |
|   2 | Liza    |
|   5 | Liza    |
|   1 | Liza    |
|   5 | Liza    |
+-----+---------+

因为我有大约 100 个名称，所以我不想像这样执行大量子查询

select null, null, thirdcolumn from...
select null, seconcolumn from...
select firstcolumn from...

有没有办法通过PIVOT或其他方式来做到这一点？

Answer 1

您可以使用动态 PIVOT 和 ROW_NUMBER() 函数来完成此操作:

DECLARE @cols AS VARCHAR(1000),
        @query  AS VARCHAR(8000)
SELECT @cols = STUFF((SELECT ',' +   QUOTENAME(Name) 
                    FROM (SELECT DISTINCT Name
                          FROM #test
                          )sub
                    ORDER BY Name
                    FOR XML PATH(''), TYPE).value('.', 'VARCHAR(MAX)') 
                    ,1,1,'')
PRINT @cols

SET @query = '
WITH cte AS (SELECT DISTINCT *
             FROM  #test)
    ,cte2 AS (SELECT *,ROW_NUMBER() OVER(PARTITION BY Name ORDER BY Apt)RowRank
             FROM  cte)
SELECT * 
FROM  cte2 
PIVOT (max(Apt) for Name in ('+@cols+')) p
            '
EXEC (@query)

SQL Fiddle - Distinct List, Specific Order

编辑:如果您不希望列表不同，请消除上面的第一个 cte，如果您想保持任意顺序，请将 ORDER BY 更改为 (SELECT 1) :

DECLARE @cols AS VARCHAR(1000),
        @query  AS VARCHAR(8000)
SELECT @cols = STUFF((SELECT ',' +   QUOTENAME(Name) 
                    FROM (SELECT DISTINCT Name
                          FROM #test
                          )sub
                          ORDER BY Name
                    FOR XML PATH(''), TYPE).value('.', 'VARCHAR(MAX)') 
                    ,1,1,'')
PRINT @cols

SET @query = '
WITH cte AS (SELECT *,ROW_NUMBER() OVER(PARTITION BY Name ORDER BY (SELECT 1))RowRank
             FROM  #test)
SELECT * 
FROM  cte 
PIVOT (max(Apt) for Name in ('+@cols+')) p
            '
EXEC (@query)

SQL Fiddle - Full List, Arbitrary Order

最后，如果您不想在结果中包含 RowRank 字段，只需在 SELECT 中重复使用 @cols 变量即可>:

SET @query = '
WITH cte AS (SELECT *,ROW_NUMBER() OVER(PARTITION BY Name ORDER BY (SELECT 1))RowRank
             FROM  #test)
SELECT '+@cols+' 
FROM  cte 
PIVOT (max(Apt) for Name in ('+@cols+')) p
            '
EXEC (@query)