It seems that OLAP treats nulls as 0 for the purpose of min/max aggregate. KB Q 244650 If I define a Measure which uses min, the null values become 0 and it affects the result. Because I have to exclude null from the min. I cannot use a calculated member with IIF and excluding null there because I have to go down too deep in the dimension (to get the min berffore the aggregations) and it becomes extremely low. I don't undestand how this basic and pretty simple thing cannot be done in a simple way. sure I can prefilter in the fact table the nulls an put a dummy extremely large value so the nulls (now converted to a large value) don't affect the min. but that seems too cumbersome. Is there an easy way ?