rows into columns [duplicate]

问题

this is my query

   select * from dbo.tblHRIS_ChildDetails where intSID=463

output:

   intCHID  intsid nvrchildname  nvrgender      dttchildDOB                   Occupation 
        3      463     SK           Female     2001-12-11 00:00:00.000  Studying    
        4      463     SM            Male      2007-10-08 00:00:00.000  Student

i need the output like this this is query is dynamic it may return n number of rows based on the intSID

chidname1   gender  DOB   childoccupation1           chidname2  gender  DOB childoccupation2 
  SK     female  2001-12-11 00:00:00.000  studying     SM        Male   2007-10-08 00:00:00.000     Student

回答1:

For this type of data, you will need to implement both the UNPIVOT and then the PIVOT functions of SQL Server. The UNPIVOT takes your data from the multiple columns and place it into two columns and then you apply the PIVOT to transform the data back into columns.

If you know all of the values that you want to transform, then you can hard-code it, similar to this:

select *
from
(
  select value, col+'_'+cast(rn as varchar(10)) col
  from
  (
    select nvrchildname,
      nvrgender,
      convert(varchar(10), dttchildDOB, 120) dttchildDOB,
      occupation,
      row_number() over(partition by intsid order by intCHID) rn
    from tblHRIS_ChildDetails
    where intsid = 463
  ) src
  unpivot
  (
    value 
    for col in (nvrchildname, nvrgender, dttchildDOB, occupation)
  ) unpiv
) src1
pivot
(
  max(value)
  for col in ([nvrchildname_1], [nvrgender_1], 
              [dttchildDOB_1], [occupation_1], 
              [nvrchildname_2], [nvrgender_2], 
              [dttchildDOB_2], [occupation_2]) 
) piv

See SQL Fiddle with Demo

Now, if you have an unknown number of values to transform, then you can use dynamic SQL for this:

DECLARE @colsUnpivot AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX),
    @colsPivot as  NVARCHAR(MAX)

select @colsUnpivot = stuff((select ','+quotename(C.name)
         from sys.columns as C
         where C.object_id = object_id('tblHRIS_ChildDetails') and
               C.name not in ('intCHID', 'intsid')
         for xml path('')), 1, 1, '')

select @colsPivot = STUFF((SELECT  ',' 
                      + quotename(c.name 
                         +'_'+ cast(t.rn as varchar(10)))
                    from 
                    (
                      select row_number() over(partition by intsid order by intCHID) rn
                      from tblHRIS_ChildDetails
                    ) t
                    cross apply sys.columns as C
                   where C.object_id = object_id('tblHRIS_ChildDetails') and
                         C.name not in ('intCHID', 'intsid')
                   group by c.name, t.rn
                   order by t.rn
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @query 
  = 'select *
      from
      (
        select col+''_''+cast(rn as varchar(10)) col, value
        from 
        (
          select nvrchildname,
            nvrgender,
            convert(varchar(10), dttchildDOB, 120) dttchildDOB,
            occupation,
            row_number() over(partition by intsid order by intCHID) rn
          from tblHRIS_ChildDetails
          where intsid = 463
        ) x
        unpivot
        (
          value
          for col in ('+ @colsunpivot +')
        ) u
      ) x1
      pivot
      (
        max(value)
        for col in  ('+ @colspivot +')
      ) p'

exec(@query)

See SQL Fiddle with Demo

The result of both queries is:

| NVRCHILDNAME_1 | NVRGENDER_1 | DTTCHILDDOB_1 | OCCUPATION_1 | NVRCHILDNAME_2 | NVRGENDER_2 | DTTCHILDDOB_2 | OCCUPATION_2 |
-----------------------------------------------------------------------------------------------------------------------------
|             SK |      Female |    2001-12-11 |     Studying |             SM |        Male |    2007-10-08 |      Student |

回答2:

You have to provide distinct column names but besides that, it's simple. But as others stated, this is not commonly done and looks like if you want print some report with two columns.

select 
  max(case when intCHID=1 then nvrchildname end) as chidname1,
  max(case when intCHID=1 then gender      end) as gender1,
  max(case when intCHID=1 then dttchildDOB end) as DOB1,
  max(case when intCHID=1 then Occupation  end) as cildOccupation1,
  max(case when intCHID=2 then nvrchildname end) as chidname2,
  max(case when intCHID=2 then gender      end) as gender2,
  max(case when intCHID=2 then dttchildDOB end) as DOB2,
  max(case when intCHID=2 then Occupation  end) as cildOccupation2
from 
  dbo.tblHRIS_ChildDetails 
where 
  intSID=463

来源：https://stackoverflow.com/questions/13599404/rows-into-columns

标签

sql

sql-server

sql-server-2005

pivot