Voor dit type gegevens moet u zowel de UNPIVOT
en dan de PIVOT
functies van SQL Server. De UNPIVOT
haalt je gegevens uit de meerdere kolommen en plaatst deze in twee kolommen en dan pas je de PIVOT
. toe om de gegevens weer in kolommen om te zetten.
Als u alle waarden kent die u wilt transformeren, kunt u deze hardcoderen, ongeveer als volgt:
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
Als u nu een onbekend aantal waarden moet transformeren, kunt u hiervoor dynamische SQL gebruiken:
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)
Het resultaat van beide zoekopdrachten 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 |