Need to calculate until a specific date in tableau? - tableau-api

Question

There are three columns, date, x, y
I need to calculate the running sum/total of y for a specific date (today's date more specifically). The data is in two datasources and looks like this in first data source.
DATE X Z
5-Sep
6-Sep 26 101
7-Sep 27 100
8-Sep 28 99
9-Sep 29 98
10-Sep 30 98
11-Sep 30 98
12-Sep 30 97
13-Sep 31 96
14-Sep 32 95
15-Sep 33 94
16-Sep 34 93
17-Sep 35 92
18-Sep 35 92
and like this is second data source
DATE Y
5-Sep 166
6-Sep 182
7-Sep 130
8-Sep 93
9-Sep 107
10-Sep 95
11-Sep 128
12-Sep 173
13-Sep 154
14-Sep 136
15-Sep 79
16-Sep 61
17-Sep 156
18-Sep 66
Lets say that today's date is 17th Sep, then I need to calculate the running sum of 'Z' until today and display it next to the 'X' column. Something like this
17-Sep 35 1499.
How do I do that?
(I tried using sets with date by limiting the date to today but then the running sum doesn't work, also there are some errors in calculated field which is because the data is in two different sources)
Please ask if need more clarification

Answer 1

Using the Super store data, I created a date parameter. Then created a calculated field as follows:
if [date param] >= [Order Date] then [Sales] end
Now this will display sales prior to your selected date parameter. I also created a filter calc to only see data prior to the selected date in the param.
[date param]>=[Order Date]
Place this in the filter shelf and select True.
Now place date field on Rows and your sales calculated field on Text pill. Right click on it and select Quick Table Calculation > Running Total.
See sample workbook here: https://www.dropbox.com/s/p42tx86v4qidlvn/170327%20stack%20question.twbx?dl=0
EDIT:
If you just want to see the total and the date selected, create a calc field for "last" as last() then filter that for zero.