你可以试试下面的代码。为您的数据库稍微更改一下，就像为SQLServer编写的一样。逻辑基本上是检查平均值（以分钟为单位），如果超过1440分钟（相当于1天），或者如果超过60分钟（相当于1小时），然后使用计算来扣除天数、小时，剩下的是分钟。

WITH test (A, B, insert_date) AS
     (SELECT 1, 2 , '2020-05-01' UNION 
      SELECT 1, 2 , '2020-05-02' UNION
      SELECT 1, 2 , '2020-05-12' UNION
      SELECT 1, 3 , '2020-05-01' UNION
      SELECT 1, 3 , '2020-05-10' UNION
      SELECT 1, 4 , '2020-05-01' UNION
      SELECT 1, 5 , '2020-05-03'
     )

SELECT *,
CASE WHEN AVG_in_minutes > 1440
     THEN CAST((AVG_in_minutes - (AVG_in_minutes % 1440))/1440 AS VARCHAR) + ' days, '
        + CAST(((AVG_in_minutes%1440 - (AVG_in_minutes%1440)%60)/60) AS VARCHAR) + ' hours, '
        + CAST(((AVG_in_minutes%1440)%60) AS VARCHAR) + ' minutes'
     WHEN AVG_in_minutes > 60
     THEN CAST(((AVG_in_minutes%1440 - (AVG_in_minutes%1440)%60)/60) AS VARCHAR) + ' hours, '
        + CAST(((AVG_in_minutes%1440)%60) AS VARCHAR) + ' minutes'
     ELSE CAST(((AVG_in_minutes%1440)%60) AS VARCHAR) + ' minutes'
     END AS AVG_in_Text
FROM
(
SELECT A, B, 
AVG(datediff(MINUTE, insert_date,current_timestamp)) AS AVG_in_minutes
from test
GROUP BY A,B
) test_final

试试这个代码。我没有测试：

with raw_data as (
SELECT A, B, AVG(date_diff('hour', creation_date,current_timestamp)) as AVG_in_hours,
AVG(date_diff('day', creation_date,current_timestamp)) as days,
AVG(date_diff('hour', creation_date,current_timestamp))- 
    AVG(date_diff('day', creation_date,current_timestamp))*24 as hrs,
AVG(date_diff('minute', creation_date,current_timestamp))- 
    AVG(date_diff('hour', creation_date,current_timestamp))*60 as minutes
FROM table
GROUP BY A,B
)

select a,b, AVG_in_hours, 
(case 
when round(days)=0 then cast(round(days) as varchar) || ' days, ' 
else '' end)
|| cast(round(hrs) as varchar) || ' hours, ' || cast(round(minutes) as varchar) || ' minutes' as AVG_TEXT
from raw_data