What's your end goal here? Do you want to show this in your workbook or is it just a once off exercise for debugging or testing for example?
i build Tableau data source and run extract , according to Tableau the most efficient way is diminish the number of columns (left menu attributes and measures) .
so after the developer done i would like to count how many columns will be in the extract.
One way to know count number of measure in datasource is drag Measure Names object in worksheet.
It will show you count of measures.
For diamension I am not sure if any predefine field available in tableau but manually you can extract data and find out number of diamension in datasource.
thank you it is a nice ,
but i think the most important are the amount of Dimensions