ORA-30452

Error: ORA-30452: cannot compute AVG(X), VARIANCE(X) or STDDEV(X), without COUNT(X) or SUM(X)

Causa: Incremental refresh of summaries requires a COUNT(X) column in order to incrementally refresh AVG(X). It requires both SUM(X) and COUNT(X) columns in order to in refresh STDDEV(X) or VARIANCE(X).

Acción: Make sure that the required columns are part of the summary definition if incremental refresh capability is desired.