I have a Google BigQuery table with a date field. When loading this table into Tableau (Tableau Desktop 10) all dates is set to null. If I change the datatype for the field to Number I get values like 42413, if I change it to String I get an "Internal Error - An unexpected error occurd and the operation could not be completed",
Suprisingly, when I hadn't looked at the data in the Data Source tab but used used the field as a date, it worked. The dates displayed were in the correct date period I extract data from. But setting a filter on the date resulted in no results (this was why I started looking into it in the first place).
So how do I get dates displayed correctly when the come from a date field in BigQuery?
Found out what's happening. Using Legacy SQL when fetching dates from BigQuery returns dates in "1900 (or 1904) Date System"-format. Using a custom sql and casting the date field to a string gives me the expected result (ie YYYY-MM-DD)