The pivot chart adds an additional function allowing you to choose an alternate method to pivot the Chart (sum, count, average, max and min).

The category and legend columns allow you to "group" the values to control how the calculation will be performed. For example: in the following scenario a category column is provided with a Pivot Function of Sum. To pivot, each SUM column value will be added together with other SUM column values having the same category MONTH value. That means that all of January would be added together to form the pivot Sum.

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In the next case there are two grouping columns, the MONTH category column,  and the ITEM legend column. To pivot in this scenario, the AMOUNT values will be group first by MONTH and then by ITEM before the Sum calculation takes place.

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