How to get the Date when Date related data available in 3 Diff fields

How to write Queries while connecting to the Excel from Tableau

1) While connecting to the Excel Database, select the Excel File then click on "Down side arrow Button" then select the "Open with Legacy Connection".

2) Now Drag the "New Custom SQL" option from left side of screen to the work Area. then It propt us to write the queries.

How to show the sales volume for specified period, it means from specified date to specified date.

1) We have to create two Parameters, 1 is for From Date, another is for to Date.

 2) Create a calculated field using two Date

 Parameters as below image.

3) Now right click on two Parameters then select the option "Show Parameter Control".

4) Now we can select the Date Range with the help of From Date Parameter To  Parameter.

Now we can handle the non selected dates data - Nulls handling.

Drag the calculated field on to filters shelf then select "Sum" option then select "Special" tab then select "non-null Values".

Now report is showing the data for selected Dates Range.