Dynamically create table columns with values from Pivot Table - sql

Question

I have a dynamic query that utilizes a pivot function and the following is an example of data in my table.
Status 1 | Week 1 |25
Status 1 | Week 1 |25
Status 1 | Week 2 |25
Status 2 | Week 1 | 2
Status 2 | Week 1 | 8
Status 2 | Week 1 | 10
Status 2 | Week 1 | 10
and this is an example of how the data is returned.
Week 1 Week 2
Status 1 | 50 25
Status 2 10 20
For my query I am passing in a week and I want to pivot on the following 5 weeks, so example, if I pass in 1, I expect to have columns from week 1 to week 6.
To help facilitate that I have written the following query.
--EXEC usp_weekReport #weeks=1, #year='2019'
ALTER PROC usp_weekReport
(
#weeks INT,
#year NVARCHAR(4)
)
AS
DECLARE #columns NVARCHAR(MAX), #sql NVARCHAR(MAX), #csql NVARCHAR(MAX);
SET #columns = N'';
SELECT #columns += N', p.' + QUOTENAME([week])
FROM (
SELECT p.[week]
FROM [Housing_support_DB].[dbo].[Invoices] P
WHERE DATEPART(YEAR,P.date)='2019'--#year
AND
([week] IN (1)
OR
[week] IN (1+1)
OR
[week] IN (1+2)
OR
[week] IN (1+3)
OR
[week] IN (1+4)
OR
[week] IN (1+5)
)
GROUP BY P.[week]
) AS x;
SET #sql = N'
SELECT p.[statusName],' + STUFF(#columns, 1, 2, '') + '
FROM
(
SELECT
SUM(CAST(REPLACE(REPLACE(A.amount,'','',''''),''$'','''') AS FLOAT)) as sumInvoice,
A.invoiceStatusID_FK,
B.statusName,
-- C.programme,
[week]
FROM [dbo].[Invoices] A
INNER JOIN invoiceStatus B
ON A.invoiceStatusID_FK=B.invoiceStatusID
-- INNER JOIN CapitalAccountBalances C
-- ON C.accountBalanceID=A.accountBalanceID_FK
-- WHERE A.accountBalanceID_FK=5
GROUP BY invoiceStatusID_FK,B.statusName,[week]--,C.programme
) AS j
PIVOT
(
SUM(sumInvoice) FOR [week] IN ('
+ STUFF(REPLACE(#columns, ', p.[', ',['), 1, 1, '')
+ ')
) AS p;';
--PRINT #sql;
EXEC sp_executesql #sql;
--SET #csql = N'
--CREATE TABLE ##reportResult
--(
--statusName nvarchar(50),'+
CREATE TABLE ##reportResult
(
statusName nvarchar(50),
weekA INT DEFAULT 0,
weekB int DEFAULT 0--,
--weekC int DEFAULT 0,
--weekD int DEFAULT 0,
--weekE int DEFAULT 0,
--weekF int DEFAULT 0
)
INSERT into ##reportResult Exec(#sql)
--INSERT ##reportResult Exec(#sql)
--SELECT statusName, weekA,weekB,weekC,weekD,weekE,weekF -- here you have "static SELECT with field names"
--FROM ##reportResult
--DROP TABLE ##reportResult
Problem
The huge problem that I have here is that, I need to send the result of this query to a tempTable...#reportResult. As a result, I need to create the table. However, if I attempt to create the table with the max amount of columns anticipated (6) I will get an invalid number of columns error. For example, in my database I only have two weeks, that's why I can only create the table with columns weekA and weekB. I also cannot do a select into.
Presently, I am trying to find a way to either create the table dynamically depending on the amount of weeks from the first part of the pivot table. Or, to manipulate the first part of the pivot to select week,week+1 etc as columns when run so that way , I can create the column with all fields.
Appreciate any help that could be provided.

Answer 1

You required dynamic SQL in your case as the column name is need to generate based on th Input week number. Below I have give you the script I created with your sample data using CTE. You just need to updated the script based on your table and requirement.
You can test the code changing the value of Week_No
For your final query, just use the SELECT part after removing the CTE code
DECLARE #Week_No INT = 2
DECLARE #Loop_Count INT = 1
DECLARE #Column_List VARCHAR(MAX) = '[Week '+CAST(#Week_No AS VARCHAR) +']'
WHILE #Loop_Count < 5
BEGIN
SET #Column_List = #Column_List +',[Week '+CAST(#Week_No+#Loop_Count AS VARCHAR) +']'
SET #Loop_Count = #Loop_Count + 1
END
--SELECT #Column_List
EXEC
('
WITH your_table(Status,Week_No,Val)
AS
(
SELECT ''Status 1'',''Week 1'',25 UNION ALL
SELECT ''Status 1'',''Week 1'',25 UNION ALL
SELECT ''Status 1'',''Week 2'',25 UNION ALL
SELECT ''Status 2'',''Week 1'',2 UNION ALL
SELECT ''Status 2'',''Week 1'',8 UNION ALL
SELECT ''Status 2'',''Week 1'',10 UNION ALL
SELECT ''Status 2'',''Week 1'',10
)
SELECT * FROM
(
SELECT * FROM your_table
) AS P
PIVOT
(
SUM(val)
FOR Week_No IN ('+#Column_List+')
)PVT
')