如何在没有游标的情况下对日期时间求和？

SELECT SUM(DATEPART(SECOND, datetime_column)) AS total_seconds,
       SUM(DATEPART(MINUTE, datetime_column)) AS total_minutes,
       SUM(DATEPART(HOUR, datetime_column)) AS total_hours,
       SUM(DATEPART(DAY, datetime_column)) AS total_days
FROM table_name;

SELECT SUM(DATEDIFF(SECOND, '1970-01-01 00:00:00', datetime_column)) AS total_seconds,
       SUM(DATEDIFF(MINUTE, '1970-01-01 00:00:00', datetime_column)) AS total_minutes,
       SUM(DATEDIFF(HOUR, '1970-01-01 00:00:00', datetime_column)) AS total_hours,
       SUM(DATEDIFF(DAY, '1970-01-01 00:00:00', datetime_column)) AS total_days
FROM table_name;