ORA-30454: summary contains STDDEV without corresponding SUM & COUNT
Cause: Incremental refresh of summaries with STDDEV(X) requires COUNT(X) and SUM(X) columns to be included in the summary definition
Action: Make sure that the required columns are part of the summary definition if incremental refresh capability is desired.
ORA-30454错误表明用户试图执行一个包含了汇总函数STDDEV的查询，而不存在汇总函数SUM及COUNT，从而导致这个错误。
当组内查询(group by queries)中包含STDDEV聚合函数，而不包含聚合函数SUM及COUNT:ORA-30454:summary contains STDDEV without corresponding SUM & COUNT
在ORACLE中，使用STDDEV函数计算同一组个数的标准偏差时，多数情况下都需要汇总函数SUM及COUNT，如果缺失其中任何一个函数，即会报ORA-30454:summary contains STDDEV without corresponding SUM & COUNT的错误。
比如：
select stdDev (sal)
from emp
group by deptno;
正确处理ORA-30454:summary contains STDDEV without corresponding SUM & COUNT错误的方法是在组内查询中同时使用汇总函数SUM及COUNT。
比如：
select sum(sal), count(sal), stdDev (sal)
from emp
group by deptno;