Summarize values using: This gives us the option to select the aggregation type. Ours is a SUM, but we can use AVG, MIN, and MAX in this type of calculation.

Moving along (or Compute using, with other table calculation types): This allows us to address the table calculation. In this example, we have only three options, namely Table (Across), Cell, or Date. The default is to compute by going across the table, which means that Tableau Public computes the values by going from left to right or top to bottom, depending on the location of the dimensions and measures.

When you click on the drop-down list, you can customize the way the field is computing by telling Tableau Public which fields to Compute using the first field, then the second, and so on. In the following screenshot, we have only one dimension, namely Year, in use. In case there were others, they would appear in the Partitioning pane, and we could add them to the Addressing pane and then sort them again. More on this will be discussed later.

The dimensions that we do not select for Compute using are used for partitioning, which is called grouping:

The next feature allows you to tell Tableau Public how many previous and future values to include, and you can also determine whether the current values should be included. Smoother lines include more previous and future values

Null if there are not enough values when selected, does not compute marks for places when there are not enough values. For instance, if you select this for this particular calculation, then the first two years in the visualization will not show a line.[tableau calculation](https://onlineitguru.com/tutorial/tableau-calculations)

Perform a secondary calculation on the result gives you the power to add additional table calculations. For instance, if this were a running sum that shows the cumulative total, we can use a percentage of the total secondary calculation to show the percentage accumulated for each year instead of the discrete number.

#Manually editing table calculations

Learning how to edit table calculations yourself is an advanced capability, but it allows you to create rich metrics, such as the percent difference from an average. In the first example, we will modify the running sum of Remittances per Capita so that it includes the preceding and next three values, which can be done from the edit table calculation dialogue by entering those numbers in their respective places. In the second example, we will modify the Remittances per Capita percent difference table calculation to show the percent difference from the average.<a href="https://onlineitguru.com/tableau-training.html"> tableau certification</a>

Let's begin with the first example. We'll modify the running sum in the following way:

1. To edit the table calculation, duplicate the sheet on which we created the original moving average worksheet, which maintains the integrity of the work that we have already done.

2. Then, drag the pill for the moving average of Remittances per Capita from the Rows shelf to the Measures shelf, which prompts us to rename it. Let's call it Smoother Remittances per Capita.

3. The original table calculation, as shown in the following screenshot, has one function, one expression, a start offset, and an end offset:

° The WINDOW_AVG function tells Tableau Public that the field can be addressed and we want it to apply the AVG function to the values

° The expression, in this case, is the field on which the calculation is operating

° The start offset, by default, is two places before end offset and hence, it has the negative sign

° The end offset, by default, is at the current value

4. Modify this calculated field to include three previous and three future values by replacing -2 and 0 with 3 and 3 respectively, as shown in the following screenshot. You can also create an integer parameter and allow users to set the number. We will show you how to do that in the chapter on parameters.

The result is a calculated field that is much smoother than the original one.

get more info about tableau calculation from [tableau online training](https://onlineitguru.com/tableau-training.html

visit