how to add grand total for discrete fields columns

Question

how to add grand total for discrete columns? Is it possible or not?

Answer 1

Hey,

You cannot add Grand Total for discrete columns.

When you try to turn on Column Grand Totals when there is a discrete measure on the Rows shelf, then the grand total for discrete measures will be blank. 
OR 
When you try to turn on Row Grand Totals when there is a discrete measure on the Rows shelf, then the following error occurs: 
Cannot turn on Grand Totals for discrete measures.

Source: https://kb.tableau.com/articles/issue/error-cannot-turn-on-grand-totals-for-discrete-measures