KB5391: What is the difference between a Database Null and a Cross-Tab Null in MicroStrategy Product Suite?
What is the difference between a Database Null and a Cross-Tab Null in MicroStrategy Product Suite?
- A Warehouse Null (DBNull) is a null value that comes directly from the data in the warehouse.
In the example below, there is a data base null value for the Unit Sales of Michael Bates because Michael Bates did not have any sales.
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Warehouse nulls may be the result of outer join settings at metric, report or database instance level.
- A Cross-Tab Null (XTABNull) is a null value that is generated in the cross-tabulation process. Cross-tabulation refers to the distribution of metric results according to the positions of attributes on the row and column axes. If all the attributes are on the row axis, cross-tabulation is trivial; the report display reflects the tabular structure of the database result.
When attributes are distributed among rows and columns, cross-tabulation determines which column a metric value should go into. If the data set does not contain a particular combination of elements for a row-column pair of attributes, cross-tabulation must produce a null value at the intersection of those attribute elements.
In the example below, note that Caitlin Bell has a cross-tab null value for Unit Sales under the manager Barbara Aoter, but not under Meredith Roe. This is generated because Caitlin Bell does not report to Barbara Aoter; so, there is no information for this combination Employee-Manager.
