I'm relatively new to Tableau, and I've just realised that LOOKUP & WINDOW_SUM don't work like I expect them to. In the attachment I have 6 rows ...
Row 1 (index) ... works exactly as I would expect
Row 2 (profit) ... simple as well, if this didn't work I'd be very worried
Row 3 (lookup first) ... not a problem, just get the first value all the time
Now the problems start:
Row 4 (lookup index) ... shouldn't this display the same as Row 2 ?
Row 5 (Window Sum) ... same way of getting the same thing right ?, well, it works the same as Row 4 but it should be working the same as Row 2
Row 6 (LAST YEAR) ... this is the problem I'm really trying to solve. There should be no values for months in 2010, and Jan 2011 should be -7379 (ie Jan 2010 value).
I don't understand how LOOKUP & WINDOW_SUM work, or are they working properly at all ?
Please let me know what I'm doing wrong.
posted a file.
