从行到列的转换称为 PIVOT，在 SQL Server 中有几种不同的方法可以完成。
聚合/案例： 您可以将聚合函数与 CASE 表达式一起使用。这将通过将row_number()窗口函数应用于表中的数据来工作：
select h_company_id, company_nm,
max(case when seq = 1 then mainphone1 end) mainphone1,
max(case when seq = 1 then phone_cnt end) phone_cnt1,
max(case when seq = 2 then mainphone1 end) mainphone2,
max(case when seq = 2 then phone_cnt end) phone_cnt2
from
(
select h_company_id, company_nm, mainphone1, phone_cnt,
row_number() over(partition by h_company_id order by mainphone1) seq
from yourtable
) d
group by h_company_id, company_nm;
请参阅SQL Fiddle with Demo。CASE 表达式检查序列号的值是 1 还是 2，然后将数据放入列中。
UNPIVOT / PIVOT： 由于您想要 PIVOT 存在于两列中的数据，那么您将需要先 UNPIVOTmainphone1和phone_cnt列以将它们放在同一列中，然后应用 PIVOT 函数。
UNPIVOT 代码将类似于以下内容：
select h_company_id, company_nm,
col+cast(seq as varchar(10)) col,
value
from
(
select h_company_id, company_nm,
cast(mainphone1 as varchar(15)) mainphone,
cast(phone_cnt as varchar(15)) phone_cnt,
row_number() over(partition by h_company_id order by mainphone1) seq
from yourtable
) d
unpivot
(
value
for col in (mainphone, phone_cnt)
) unpiv;
请参阅演示。此查询以下列格式获取数据：
| H_COMPANY_ID | COMPANY_NM | COL | VALUE |
---------------------------------------------------------------
| 11043 | 3I Group PLC | mainphone1 | 2079753731 |
| 11043 | 3I Group PLC | phone_cnt1 | 15 |
| 11043 | 3I Group PLC | mainphone2 | 2079757115 |
| 11043 | 3I Group PLC | phone_cnt2 | 1 |
| 20816 | 800 Flowers | mainphone1 | 5162377000 |
然后将 PIVOT 函数应用于 中的值col：
select h_company_id, company_nm,
mainphone1, phone_cnt1, mainphone2, phone_cnt2
from
(
select h_company_id, company_nm,
col+cast(seq as varchar(10)) col,
value
from
(
select h_company_id, company_nm,
cast(mainphone1 as varchar(15)) mainphone,
cast(phone_cnt as varchar(15)) phone_cnt,
row_number() over(partition by h_company_id order by mainphone1) seq
from yourtable
) d
unpivot
(
value
for col in (mainphone, phone_cnt)
) unpiv
) src
pivot
(
max(value)
for col in (mainphone1, phone_cnt1, mainphone2, phone_cnt2)
) piv;
请参阅SQL Fiddle with Demo。
多次加入：您还可以多次加入您的表以获得结果。
;with cte as
(
select h_company_id, company_nm, mainphone1, phone_cnt,
row_number() over(partition by h_company_id order by mainphone1) seq
from yourtable
)
select c1.h_company_id,
c1.company_nm,
c1.mainphone1,
c1.phone_cnt phone_cnt1,
c2.mainphone1 mainphone2,
c2.phone_cnt phone_cnt2
from cte c1
left join cte c2
on c1.h_company_id = c2.h_company_id
and c2.seq = 2
where c1.seq = 1;
请参阅SQL Fiddle with Demo。
动态 SQL：最后，如果您有未知数量的值要转换，那么您将需要实现动态 SQL 以获得结果：
DECLARE @cols AS NVARCHAR(MAX),
@query AS NVARCHAR(MAX)
select @cols = STUFF((SELECT ',' + QUOTENAME(col+cast(seq as varchar(10)))
from
(
select row_number() over(partition by h_company_id order by mainphone1) seq
from yourtable
) d
cross apply
(
select 'mainphone', 1 union all
select 'phone_cnt', 2
) c (col, so)
group by seq, so, col
order by seq, so
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')
set @query = 'SELECT h_company_id, company_nm,' + @cols + '
from
(
select h_company_id, company_nm,
col+cast(seq as varchar(10)) col,
value
from
(
select h_company_id, company_nm,
cast(mainphone1 as varchar(15)) mainphone,
cast(phone_cnt as varchar(15)) phone_cnt,
row_number() over(partition by h_company_id order by mainphone1) seq
from yourtable
) d
unpivot
(
value
for col in (mainphone, phone_cnt)
) unpiv
) x
pivot
(
max(value)
for col in (' + @cols + ')
) p '
execute(@query)
请参阅SQL Fiddle with Demo。都给出一个结果：
| H_COMPANY_ID | COMPANY_NM | MAINPHONE1 | PHONE_CNT1 | MAINPHONE2 | PHONE_CNT2 |
-----------------------------------------------------------------------------------------
| 20820 | 1st Source Corp. | 5742353000 | 3 | (null) | (null) |
| 20821 | 1st United Bancorp | 5613633400 | 2 | (null) | (null) |
| 20824 | 3D Systems Inc. | 8033273900 | 4 | 8033464010 | 1 |
| 11043 | 3I Group PLC | 2079753731 | 15 | 2079757115 | 1 |
| 20816 | 800 Flowers | 5162377000 | 3 | 5162377131 | 1 |