联合列值分为一行

Question

我有一个具有这种结构的平板电脑：

Usr    Key        Value
Peter   Address    78 Street
Peter   Number     123456
Peter   Sport      Rugby
Peter   Document   ABCDE

我想对此进行查询：

NAME  Address   Number Sport Document
Peter 78 Street 123456 Rugby ABCDE

谁能帮帮我？

Answer 1

如果每个用户的每个密钥只有一个值：

select P.*
from Table1 as t
pivot (
    max(Value)
    for [Key] in ([Address], [Number], [Sport], [Document])
) as P

或

select
    t.Usr,
    max(case when t.[Key] = 'Address' then t.[Value] end) as Address,
    max(case when t.[Key] = 'Number' then t.[Value] end) as Number,
    max(case when t.[Key] = 'Sport' then t.[Value] end) as Sport,
    max(case when t.[Key] = 'Document' then t.[Value] end) as Document
from Table1 as t
group by t.Usr

<强> sql fiddle demo

Answer 2

您应该查看此link以获取有关PIVOT语句的更多信息。至于你的问题，这是一个如何做到的例子：

--create temp table and populate it
SELECT 'NAME' AS [KEY], 'Peter' AS VALUE
INTO #tmp
UNION ALL
SELECT 'Address' AS [KEY], '78' AS VALUE
UNION ALL
SELECT 'Number' AS [KEY], '1' AS VALUE
UNION ALL
SELECT 'Sport' AS [KEY], 'Rugby' AS VALUE
UNION ALL
SELECT 'Document' AS [KEY], 'qwretz' AS VALUE

--check what's in here
SELECT [KEY], VALUE FROM #tmp

--pivot
SELECT [NAME], [Address], [Number], [Sport], [DOCUMENT]
FROM
( SELECT [KEY], VALUE FROM #tmp) AS SourceTable
PIVOT
( MAX(VALUE)
FOR [KEY] IN ([NAME], [Address], [Number], [Sport], [DOCUMENT])
) AS PivotTable