主题：【求助】一个MySQL query的问题 -- 阿国

--assume timestamp is integer

select abclog_id, sum(case when log_typeid = 82 then timestamp else 0 end) - sum(case when log_typeid = 81 then timestamp else 0 end) as [time]

from table_one

where abclog_id = 247927204 and log_type_id in (81, 82)

group by abclog_id

MySQL 不熟，估计原理差不多吧，就是巧用group by而已。