对查询的某些修改将获取结果。试试这个。

Some modification to your query will fetch the result. Try this.

SELECT FormKey,
       Stuff((SELECT ',' + Value
              FROM   Result b
              WHERE  a.FormKey = b.FormKey
                     AND a.Category = b.Category
              FOR xml path('')), 1, 1, '') value,
       Category
FROM   Result a
GROUP  BY FormKey,
          Category