Having Trouble with FOR XML Path - No Concatenating - sql

Question

I have a situation where an order can contain multiple license purchases - and if the order does contain multiple licenses, I want to display the license descriptions in a single cell with the values separated by commas. If we were on SQL 2017, I could use STRING_AGG but we are on SQL 2016 so I am trying the tried and true STUFF / FOR XML Path method.
From the screenshot below, Customer 4341073 had two license purchases on Order ID 18519173:
When I add the STUFF / FOR XML Path to the T-SQL, I am not able to achieve the desired result of showing the license description in the same record - each license still has it's own row.
SELECT x.CustomerID ,
x.ATOLicenseTypeID ,
x.ATOLicense ,
x.AuthorizationBeginDate ,
x.AuthorizationEndDate ,
x.OrderID ,
x.OrderDate ,
STUFF ( (
SELECT ',' + lt.description
FROM dbo.LicenseTypes AS lt
--INNER JOIN #XMLPATH ON lt.id = x.OrderLicenseTypeID
WHERE lt.id = x.OrderLicenseTypeID
--GROUP BY ',' + lt.description
FOR XML PATH ( '' )
) , 1 , 1 , '' ) AS Licenses
FROM #XMLPATH AS x
--GROUP BY x.CustomerID ,
-- x.ATOLicenseTypeID ,
-- x.ATOLicense ,
-- x.AuthorizationBeginDate ,
-- x.AuthorizationEndDate ,
-- x.OrderID ,
-- x.OrderDate ,
-- x.OrderLicenseTypeID;
I've tried different ways to join the sub-query to the outer query and added and removed GROUP BY to achieve the desired result but nothing is working for me.
Any suggestions on where I am going wrong with this query?
Sample dataset:
DROP TABLE IF EXISTS #XMLPATH;
CREATE TABLE #XMLPATH
(
CustomerID INT ,
ATOLicenseTypeID INT ,
ATOLicense VARCHAR (500) ,
AuthorizationBeginDate DATE ,
AuthorizationEndDate DATE ,
OrderID INT ,
OrderDate DATETIME ,
OrderLicenseTypeID INT
);
INSERT INTO #XMLPATH
VALUES ( 4341073, 52, 'Temporary Resident Fishing', N'2019-01-07T00:00:00', N'2019-01-07T00:00:00', 18519136, N'2019-01-07T12:01:55.317', 2141 ) ,
( 4341073, 52, 'Temporary Resident Fishing', N'2019-01-07T00:00:00', N'2019-01-07T00:00:00', 18519173, N'2019-01-07T12:34:13.107', 204 ) ,
( 4341073, 52, 'Temporary Resident Fishing', N'2019-01-07T00:00:00', N'2019-01-07T00:00:00', 18519173, N'2019-01-07T12:34:13.107', 2141 );
SELECT * FROM #XMLPATH;
SELECT x.CustomerID ,
x.ATOLicenseTypeID ,
x.ATOLicense ,
x.AuthorizationBeginDate ,
x.AuthorizationEndDate ,
x.OrderID ,
x.OrderDate ,
STUFF ( (
SELECT ',' + lt.description
FROM dbo.LicenseTypes AS lt
--INNER JOIN #XMLPATH ON lt.id = x.OrderLicenseTypeID
WHERE lt.id = x.OrderLicenseTypeID
--GROUP BY ',' + lt.description
FOR XML PATH ( '' )
) , 1 , 1 , '' ) AS Licenses
FROM #XMLPATH AS x
GROUP BY x.CustomerID ,
x.ATOLicenseTypeID ,
x.ATOLicense ,
x.AuthorizationBeginDate ,
x.AuthorizationEndDate ,
x.OrderID ,
x.OrderDate ,
x.OrderLicenseTypeID;

Answer 1

In order to get all rows of one OrderID as one result-row, you must not include the separating information (the OrderLicenseTypeID) into the GROUP BY. But then you have the issue you've encountered: You cannot use this ID within your FOR XML construct.
The trick is (as your out-commented trials show), to add the source table to the sub-select and filter there with a grouped column. But you have to use different aliases to deal with them as two different sets. Try this:
(I had to add one more temp table to test this...)
SELECT x.CustomerID ,
x.ATOLicenseTypeID ,
x.ATOLicense ,
x.AuthorizationBeginDate ,
x.AuthorizationEndDate ,
x.OrderID ,
x.OrderDate ,
STUFF ( (
SELECT ',' + lt.description
FROM #XMLPATH x2
INNER JOIN #LicenseTypes AS lt ON lt.id=x2.OrderLicenseTypeID
WHERE x2.OrderID = x.OrderID --you might need to add more columns here....
--in most cases we want to add an ORDER BY
FOR XML PATH ( '' )
) , 1 , 1 , '' ) AS Licenses
FROM #XMLPATH AS x
GROUP BY x.CustomerID ,
x.ATOLicenseTypeID ,
x.ATOLicense ,
x.AuthorizationBeginDate ,
x.AuthorizationEndDate ,
x.OrderID ,
x.OrderDate;
Btw: Starting with v2017 there is STRING_AGG(), which makes this much easier...