SQL Server SORT Dynamic Pivot Column Names - sql

Question

I have an dynamic SQL query which is returning the result as desired but the only problem is the resultant pivot columns are not getting selected in correct order.
I am using SQL Server 2012.
Here is the query:
DECLARE #columns NVARCHAR(MAX), #columns_pivot NVARCHAR(MAX), #sql NVARCHAR(MAX);
SELECT #columns_pivot = COALESCE(#columns_pivot + ', ', '') + QUOTENAME(Week_No)
,#columns = COALESCE(#columns + ', ', '') + 'ISNULL(' + QUOTENAME(Week_No) + ',0) AS ' + QUOTENAME(Week_No) + ''
FROM (SELECT DISTINCT TOP 100 PERCENT DATEPART(wk,T_Date) As Week_No
FROM [VISIT].[dbo].[Report]
WHERE DATEPART(m,T_Date) = 5
ORDER BY Week_No DESC) x; // This query returns Column 'Week_No' in order 22,21,20,19,18 (As Desired)
Edit: //But when Order By Clause is removed it returns 21,18,19,22,20 which is the actual output( Not Desired)
SET #sql = '
SELECT ABC, ' + #columns + '
FROM
(Select TOP 100 PERCENT
ABC
,SUM(CASE WHEN Type = A THEN Sum ELSE 0 END) AS Revenue
,DATEPART(wk,T_Date) As Week_No
FROM [VISIT].[dbo].[Report]
GROUP BY ABC
,DATEPART(wk,T_Date)
ORDER BY Week_No DESC) As j
PIVOT(
max(Revenue)
FOR Week_No in (' + #columns_pivot + ')) As p '
Final result returns columns in the order ABC, 21, 18, 19, 22, 20
But I want the result As ABC, 22, 21, 20, 19, 18.
I saw few posts but was not able to figure out what is wrong with my query. Can someone please point what I have to change in the Query to get the desired output. Where exactly do I have to put the ORDER BY clause
In short when the Select Distinct statement returns the column Week_No in Desc Order why the variables #columns and #columns_pivot don't get it in Desc order
Thanks.

Answer 1

I have solved the issue by storing Week_No in a temp table and apply clustered indexing to it.
Here is the code I added:
IF OBJECT_ID('tempdb..#temp') IS NOT NULL
DROP TABLE #temp
SET NOCOUNT ON;
DECLARE #params nvarchar(max) = :month
SELECT DISTINCT TOP 100 PERCENT DATEPART(wk,Tour_Datum) As Week_No into #temp
FROM [VISITOUR].[dbo].[BI_001_ADM_Report]
WHERE DATEPART(m,Tour_Datum) = #params
--Clustered index is created on week_no in acending order, so that data is physically stored in that way
CREATE CLUSTERED INDEX cix_wekno ON #temp(Week_No ASC)