Dynamic Pivot SQL with multiple aggregations - sql

Question

I have a query that pulls through a dynamic list of columns (ie the columns can change at any time) and pivots the data showing he Maximum InstalledDate for those columns. My question is however, how do I pull through more than one aggregation? I need to have the Max LocationCode, MakeCode and ModelCode for each PlaceRef too but am struggling to do this. Many thanks in advance.
DECLARE #columns NVARCHAR(MAX), #sql NVARCHAR(MAX);
SET #columns = N'';
SELECT #columns += N', p.' + QUOTENAME(Component )
FROM (SELECT p.Component FROM VwLocationComponentCurrent AS p
INNER JOIN VwLocationListEntriesCurrent AS o ON p.PlaceRef = o.PlaceRef
where o.LocationList = N'NEWBUILD'
GROUP BY p.Component) AS x;
SET #sql = N'
SELECT PlaceRef, Address1, StreetName, PostCode, Substatus, BuildingType, BuildDate, ' + STUFF(#columns , 1, 2, '') + '
FROM
(
SELECT
vwLocationCurrent.PlaceRef
,vwLocationCurrent.BuildDate
,vwLocationCurrent.SubStatus
,vwLocationCurrent.StreetName
,vwLocationCurrent.Address1
,vwLocationCurrent.Address2
,vwLocationCurrent.Address3
,vwLocationCurrent.PostCode
,VwLocationComponentCurrent.Component
,VwLocationComponentCurrent.SubLocationCode
,VwLocationComponentCurrent.InstalledDate
,VwLocationComponentCurrent.MakeCode
,VwLocationComponentCurrent.ModelCode
,VwLocationListEntriesCurrent.LocationList
,vwLocationCurrent.BuildingType
FROM
vwLocationCurrent
INNER JOIN VwLocationListEntriesCurrent
ON vwLocationCurrent.PlaceRef = VwLocationListEntriesCurrent.PlaceRef
LEFT OUTER JOIN VwLocationComponentCurrent
ON vwLocationCurrent.PlaceRef = VwLocationComponentCurrent.PlaceRef
WHERE
VwLocationListEntriesCurrent.LocationList = ''NEWBUILD''
) AS j
PIVOT
(
MAX(InstalledDate) FOR Component IN ('
+ STUFF(REPLACE(#columns, ', p.[', ',['), 1, 1, '')
+ ')
) AS p;'
;
PRINT #sql;
EXEC sp_executesql #sql;

Answer 1

I suggest you don't use the "pivot" feature here, instead use an older technique employing "conditional aggregates". This means the creation of the "columns" string is more complex but it does allow you to output multiple aggregations in a single query. The following code is untested as there is no sample data to work with:
DECLARE #columns nvarchar(max)
, #sql nvarchar(max);
SET #columns = N'';
SELECT
#columns +=
+ N', max(case when Component = p.' + QUOTENAME(Component) + N' then SubLocationCode end) as ' + QUOTENAME('Loc_' + Component)
+ N', max(case when Component = p.' + QUOTENAME(Component) + N' then MakeCode end) as ' + QUOTENAME('Mak_' + Component)
+ N', max(case when Component = p.' + QUOTENAME(Component) + N' then ModelCode end) as '+ QUOTENAME('Mod_' + Component)
FROM (
SELECT
p.Component
FROM VwLocationComponentCurrent AS p
INNER JOIN VwLocationListEntriesCurrent AS o ON p.PlaceRef = o.PlaceRef
WHERE o.LocationList = N'NEWBUILD'
GROUP BY
p.Component
) AS x;
SET #sql = N'
SELECT PlaceRef, Address1, StreetName, PostCode, SubStatus, BuildingType, BuildDate, ' + STUFF(#columns, 1, 2, '') + '
FROM
(
SELECT
vwLocationCurrent.PlaceRef
,vwLocationCurrent.Address1
,vwLocationCurrent.StreetName
,vwLocationCurrent.PostCode
,vwLocationCurrent.SubStatus
,vwLocationCurrent.BuildingType
,vwLocationCurrent.BuildDate'
+ STUFF(REPLACE(#columns, ', p.[', ',['), 1, 1, '')
+ N' FROM vwLocationCurrent
INNER JOIN VwLocationListEntriesCurrent
ON vwLocationCurrent.PlaceRef = VwLocationListEntriesCurrent.PlaceRef
LEFT OUTER JOIN VwLocationComponentCurrent
ON vwLocationCurrent.PlaceRef = VwLocationComponentCurrent.PlaceRef
WHERE VwLocationListEntriesCurrent.LocationList = ''NEWBUILD''
GROUP BY
vwLocationCurrent.PlaceRef
,vwLocationCurrent.Address1
,vwLocationCurrent.StreetName
,vwLocationCurrent.PostCode
,vwLocationCurrent.SubStatus
,vwLocationCurrent.BuildingType
) AS p;'
;
PRINT #sql;
EXEC sp_executesql #sql;