添加total_事件的新列

你可以使用 window function

SELECT
    wait_event_type,
    wait_event,
    event_count,
    SUM(event_count) OVER (PARTITION BY wait_event_type) AS total_event_count
FROM my_table

You can also use group by clause and join 

select m.wait_event_type, m.wait_event, m.event_count, t.total_event_count from (select wait_event_type,SUM(event_count) as total_event_count from my_table group by wait_event_type)t join my_table m on m.wait_event_type=t.wait_event_type