select id, (col1+col2+ col3)/3 as avgVal from T1 where id=123
select tn.date,case when tn.type=a then avg(tn.value) end as 'a',case when tn.type=b then avg(tn.value) end as 'b' from table_name tn group by tn.date简单的叙述了下。可能有漏考虑的勿怪
select start, end, avg(value) from (
select t2.start, t2.end, t1.value from t1 left join t2 on t1.key between t2.start and t2.end
) as x group by start,end
效果见下图:
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