一种方法是在这里使用嵌套查询。我在外部查询中筛选到section'A'，然后在这里关联查询：

SELECT Section AS [@type],
       COUNT(*) [@count],
       (SELECT class as [@class],
               studentName AS [@studentName]
        FROM dbo.school sN
        WHERE sN.section = s.section
        FOR XML PATH('instance'),TYPE)
FROM dbo.school s
WHERE s.section = 'A'
GROUP BY s.section
FOR XML PATH('listResponse');