I am trying to import a text file where one of the columns contains varchar2 data with entries including 0111111111, 9999999999, B999999999. Tableau is converting the entire column to a measure and any non-number, or number starting with 0, becomes a null. They remain nulls if I change the data type to string after the import. How can I tell Tableau this is a string during the import?
I think you may need to create an explicit schema.ini file, as described here:
There are some threads out there on the forum about this that you should be able to find, as well.