oracle 求标准偏差:
select STDdEV(column1) from (
select 50 column1 from dual
union
select 90 from dual
union
select 70 from dual) tt


sqlserver 里求标准偏差:
select STDEV(column1) from (
select 50 column1
union
select 90
union
select 70 ) tt[@more@]