1 of 1 people found this helpful
SUM(sales) is at the cell level. In your screen shot the SUM(sales) for each customer is about 95K, 85K, 78K, 62K, 57K.
RANK(SUM(sales)) ranks those values.
When you are editing a calc, you can click on the function name (always in blue in the editor) and off to the right is a panel that explains what that function does, and the parameters needed for that function (if any).
SIZE() tells Tableau how many rows are in that partition. In your screen shot, SIZE() = 5.
A really helpful thing to do when you are trying out what a function is doing is to display its value on the sheet. Create a calc that just says SIZE(). Drag that to the text shelf. And drag the [rankofsales] calc to the text shelf. These numbers would then display on each row, and then you would see what the larger calc is doing.
i understood rank part thankyou