how to use MAX for multiple values in dyamnmic Pivot - sql

Question

I have a query when I'm using static Dynamic pivot it is working fine
Static Script :
Select Name, tableName,MAX([2017-07-10])[2017-07-10],MAX([2017-07-09])[2017-07-09]
from (
SELECT Target_Db_Name,
Target_Tbl_Name,
Cnt
FROM Table1 l
WHERE Name='Employee' AND
dt >= CAST(dateadd(day, -1, getdate()) as date))T
PIVOT (MAX(cnt)FOR dt IN ([2017-07-10],[2017-07-09]) )PVT
GROUP BY Name, tableName
when I'm trying to implement dynamic query in the same query I'm confused to get max values for multiple comma separated data values
Dynamic Script :
DECLARE #cols AS NVARCHAR(MAX)='';
DECLARE #query AS NVARCHAR(MAX)='';
SELECT #cols = #cols + QUOTENAME(dt) + ',' FROM (select distinct CONVERT(DATE,t)Start_dt from Events
WHERE Start_dt >= CAST(dateadd(day, -1, getdate()) as date) ) as tmp ORDER BY Start_dt desc
select #cols = substring(#cols, 0, len(#cols))
Select #query = '
Select Name, tableName,'+#cols+'
from (
SELECT Name,
tableName,
Cnt
FROM Table1 l
WHERE Name=''Employee'' AND
Start_dt >= CAST(dateadd(day, -1, getdate()) as date))T
PIVOT (MAX(Cnt)FOR Start_dt IN ('+#cols+') )PVT
GROUP BY Name, tableName
'
EXEC (#query)
So here date values are coming like this
([2017-07-10]),([2017-07-09]) in dynamic how to apply
MAX([2017-07-10]),MAX([2017-07-09])
how to get max for each date in Dynamic Pivot

Answer 1

Here is one way to get the Max aggregate in column list
SET #cols = stuff((SELECT DISTINCT ','+Quotename(CONVERT(DATE, Start_dt))
FROM Events
WHERE Start_dt >= Cast(Dateadd(day, -1, Getdate()) AS DATE)
ORDER BY Start_dt DESC
FOR xml path('')) ,1,1,'')
--Print #cols
SET #select_cols = stuff((SELECT DISTINCT ',Max('+Quotename(CONVERT(DATE, Start_dt))+') as '+Quotename(CONVERT(DATE, t))
FROM Events
WHERE Start_dt >= Cast(Dateadd(day, -1, Getdate()) AS DATE)
ORDER BY Start_dt DESC
FOR xml path('')) ,1,1,'')
--Print #select_cols
Select #query = '
Select Name, tableName,'+#select_cols+'
from (
SELECT Name,
tableName,
Cnt
FROM Table1 l
WHERE Name=''Employee'' AND
Start_dt >= CAST(dateadd(day, -1, getdate()) as date))T
PIVOT (MAX(Cnt)FOR Start_dt IN ('+#cols+') )PVT
GROUP BY Name, tableName
'
EXEC (#query)
Note : Your current method to convert rows into csv's isn't guaranteed to work all the time. I have used for xml path() method to do the same