Tableau subtract two columns

Hi Brad - how do you get the one column to not display then (the % Diff Qt that has no data under it)  I have a dataset that I need to work as follows:

               Dec14          YTD          Variance

A               20              32                12

B               15               21                6

What I get when I use your suggestion is more like:

               Dec14      Variance      YTD     Variance

A               20                                32             12

B               15                                21              6

I need to remove the first Variance column?

Issue

Environment

Resolution

Option 1

1. In Tableau Desktop, right-click the sheet name and select Duplicate sheet. This will retain the view structure (such as YEAR on Columns and Measures on Text, etc).
2. Navigate to Analysis > Create calculated field
3. Name the calculated field and enter a formula similar to the following: SUM([Sales]) - LOOKUP(ZN(SUM([Sales])), -2)Note: -2 is calculated as “two cells previous”. If the data were viewed in a table, this means that the calculation will subtract the number two columns previous from the current column. If the view is changed from YEAR to QUARTER, this will change the result from 2 years previous to 2 quarters previous. 

1. Drag the new calculation to the view, replacing the original measure.

To isolate one desired value for the calculation:

1.  Create a calculated field with a name like "Last Filter" with a calculation similar to the following: LAST() = 0
2. Drag [Last Filter] to the Filters shelf
3. In the Filter dialog, check True and click OK
4. Right-click on Year, clear the Show Header selection.

Option 2

1. Use the method in Isolating Dimension Members to Use in Calculations and Filters to create separate calculated for sales for each year
2. Create a calculated field with a name like "Sales Difference (option 2)" with a calculation similar to the following: SUM([ Sales]) - SUM([ Sales])
3. Drag [Sales Difference (option 2)] to Text on the Marks card

Cause

Additional Information

Sure! My pleasure!

See this is the calculated field which I've used to calculate the difference.

Here,

ZN() function replace null to zero, If found.

LOOKUP() function is the interesting part which doing your job

In the Difference table calculation, we want to compare a value against itself in a previous (or simply, a different) partition. Notice how the second value in the calculation is wrapped in a LOOKUP() function, which "looks" at the previous partition's value and then subtracts it from the next one, etc. The -1 declares which partition is in relation to the base of the calculation.

Mahfooj

I have two columns that I am trying to find the difference from rather than the total. Can someone help me set up the formula?

To compare data from two fields and calculate the difference, you can use the LOOKUP function. Assuming you have data in fields for and , then you could use the following expression to find the difference:

LOOKUP( &#;Returns the value of the expression in a target row, specified as a relative offset from the current row. Use FIRST() + n and LAST() &#; n as part of your offset definition for a target relative to the first/last rows in the partition. If offset is omitted, the row to compare to can be set on the field menu. This function returns NULL if the target row cannot be determined.

SUM([OrderQty]), &#;here we specify data aggregation

LAST()) &#;  here we specify the offset

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