Are the zeroes chopped of by Tableau, or in Excel?
I think Tableau is exporting the fields correct as a string (including the zeroes), but Excel is interpreting these as a number, and chopping of the zeroes.
You can check this if you look a the exported file in a text-editor, like notepad.
I tested it with some dummy data, and the export (right on the screenshot) is fine, but Excel is nterpreting this wrong.
If you import the csv file in Excel, you need to specify that your data-field is a string, not general or number:
Does this help you out?
Johan de Groot
I've ran into this issue in the past and Tableau gave the following explanation:
To be absolutely sure that data gets exported correctly to Excel, Tableau has decided to let Excel decided what kind of format should be used. So numbers will always turn into integer and not to text even if it is a string in Tableau.