Testdata
DECLARE @t TABLE ([StopNumber] INT, [DumpsterNumber] VARCHAR(10))
INSERT INTO @t
VALUES
(1,'245'),
(1,'248'),
(2,'312'),
(2,'314'),
(2,'316')
Fråga
SELECT t.[StopNumber]
,STUFF((SELECT ', ' + [DumpsterNumber]
FROM TestTableOne
WHERE [StopNumber] = t.StopNumber
FOR XML PATH(''), TYPE
).value('.', 'varchar(max)'), 1, 2, '') AS [DumpsterNumber]
FROM TestTableOne t
GROUP BY t.[StopNumber]
Resultatuppsättning
╔════════════╦════════════════╗
║ StopNumber ║ DumpsterNumber ║
╠════════════╬════════════════╣
║ 1 ║ 245, 248 ║
║ 2 ║ 312, 314, 316 ║
╚════════════╩════════════════╝