Hey All, WDF question. How does a WDF handle null...
# gooddata-cloud
Hey All, WDF question. How does a WDF handle null values? Scenario: • I have a list of items that are global • For some accounts they have additional items in that list If I have a WDF that is on an account id, then I have null values in the global items, would those be included or excluded from being included in all accounts
In general it is recommended to include all possible values in dimension dataset otherwise some values which will appear in data will be not available in filters. In case there is a NULL value in the fact dataset it is recommended to replace it by some special value (e.g. “N/A”) and include it to the dimension dataset, so that it can be filtered out as well.
Currently NULL values are excluded - we generate something like
WHERE wdf_column IN ('values1'. 'value2', ...)
. Anyway, the concept described by @Joseph Heun is strongly recommended - we don't want to JOIN tables by NULL values, it would negatively affect the performance of JOIN operations.