如何编写与此本机sql相对应的JPA Criteria API Query？

Question

我有一个生日字段作为日期类型，如果想按年龄范围对所有使用数据进行分组我已经有了以下sql代码来执行解决方案，但我需要与此对应的条件api查询。如何编写以下代码的条件查询??

WITH AgeData as
(
     SELECT [Username],
     [Birthdate],
     DATEDIFF(YEAR, [Birthdate], GETDATE()) AS [AGE]
    FROM @table
),
GroupAge AS
(
     SELECT [Username],
     [Birthdate],
     [Age],
     CASE
         WHEN AGE < 30 THEN 'Under 30'
         WHEN AGE BETWEEN 31 AND 40 THEN '31 - 40'
         WHEN AGE BETWEEN 41 AND 50 THEN '41 - 50'
         WHEN AGE > 50 THEN 'Over 50'
         ELSE 'Invalid Birthdate'
     END AS [Age Groups]
 FROM AgeData
)

SELECT COUNT(*) AS [AgeGrpCount],
    [Age Groups]
FROM GroupAge
GROUP BY [Age Groups];