Date calculation - Tableau - tableau-api

We have data that is submitted that is only YTD numbers. I'm wondering how I could display numbers that are subtracted along the Date field.
Ie, if I want to show the MTD movement on March. I will have to go March less February.
Now I know I can do this for individual measure fields. But having around 40+ measures seems a bit tedious.
http://kb.tableausoftware.com/articles/knowledgebase/creating-ytd-mtd-calculations
I tried to enter "Measure Values" but that is not a valid measure to put in the calculation.
Is there a way to set up a custom dimension?
Thanks,
Gem

After days of research, can't be done in tableau unless you want to labour for a week creating an almost cell by cell calculation. Data transformation in SQL will be a more feasible solution.
I had pivoted the data previously in SQL, so that I end up with 1 measure column instead of 40+. That enables you to minimise the calculation fields, so that you don't have to repeat all the calculation for individual measures.
Works well. Not for ratios though, as you will need to extract individual measures again so that you can divide them against each other. It's got pros and cons. Number of rows in the DB also multiplies.
Other solutions that preserves the table structure will be to use temp tables and do calculations on several temp tables.

Related

Why are my values multiplying when I apply Month/Year to my values?

When I apply Month/Year to Cases or Deaths from my data, the values explode. For Cases it goes from approximately 48 million to over 1 billion, and for Deaths it goes from about 700 thousand to over 22 million. However, when I try the same thing with Initial Claims or the Stringency Index, my values remain correct. I'm trying to find the month over month percentage change by the way. And I'm using the Date column. I only select 2020 and 2021 in the filter for Year.
What I'm asking about is Sheet 21.
Link to workbook: https://public.tableau.com/app/profile/nilajah.rivers/viz/CoronaVirusProject_16323687296770/Sheet21
Your problem is that the data points are daily cumulative deaths. If you change the date aggregation to anything other than days, Tableau will default to summing the numbers for all the days in the month. This will give the wrong result, obviously.
If you want to show the correct total deaths or cases regardless of the time aggregation (months, days, weeks etc.) then you could use the New Case or New Death numbers plus a running sum table calculation. This will always give the correct total for the time period.
Table calculations will also allow automatic calculation of the period to period % change from the same data fields.
This is a common problem when working with datasets that offer pre-calculated aggregations. Tableau doesn't need that as it can dynamically calculate the aggregation of a field over any given time period but it is easy to forget which field has pre-aggregated data and which has raw data. Pre-aggregated fields assume a particular time period and can't be used for different time periods without disentangling that assumption (which is unnecessary if you also have the raw data (in this case daily new deaths/cases).

Aggregating data from the US stock market in Tableau, using different time frames

I am a very basic user of tableau and I have not found an answer to my question.
I have a txt file that has historical daily data for 98% of all the stocks in the US, with their daily capitalization. Each stocks has its TICKER, Daily Market Value for every trading day of the year, and its SECTOR.
I did a simple time series that display SUM([Mktval]) (sum of all individual market values) across all stocks, on a daily daily, and where I can see that the total value as of 2016 is about 24 Trillion USD, as in the image below.
When I change the view column from DAY to YEAR, I don't see the right values, but something a lot larger. So I realized that I need to do SUM([Mktval])/252 to get the right value for a year (there are 252 trading days in a year).
If I change the view to MONTH, as in the chart below, the numbers are again wrong because 252 is not the right value to use in the division.
Is there any way that Tableau can adjust the values automatically to reflect the AVG MktVal across different time intervals?
Thanks
Replace SUM(Mktval) on the Rows shelf with the following calculated field
avg({ fixed day(Date1) : sum(Mktval) })
That solution is all in one step. It is perhaps a bit more clear to use 2 steps. First, create a calculated field called total_daily_market_value defined as
{ fixed day(Date1) : sum(Mktval) }
Then make sure that calculated field is a measure. It is an LOD calculation that you can think of as a separate table with one value for each day showing the total market value for that day.
Drag that measure to a shelf, and then change the aggregation function to AVG(), MEDIAN(), MIN(), MAX() or STDEV() as desired. Tableau will aggregate the total_daily_market_value using your chosen aggregation function for whatever values of Date1 are in your view.

Tableau : How to get the Dashboard always display the latest 10 days worth of group statistics

My input text source always contains last 12 months worth of data. e.g: Current month is October. So My input source contains data starting from last Oct 1st to till date. But I want the aggregate statistics to be displayed on a daily basis for last 10 days of sales , 30 days of sales, 45 days of sale per product across various regions
I am trying to use window_avg fuction with something like window_avg(sum(sales), first() + datediff('day', window_min(min([date]))-1, dateadd('month',1,window_min(min([Date]))-1)) * 13,13) something like that. But I am not able to crack the exact logic.
Could you please suggest me some better way to achieve this, rather than using these kind of calculations. Also I am afraid if this goes wrong if there is data missing in the middle one or two days.
Any help is appreciated.
A very simple thing is to use a relative date filter. There's a UI for you to select they last N days.
Put the date on the columns shelf and set it to the date truncation of year-month-days. Put your measure row shelf. Put the date pill on the filter shelf too and use a relative date filter.
If you are doing simple aggregate like the sum of sales for a day it's easy and you'll not need to do anything else. You can can also fairly easily create a table calculation by right clicking on the measure and choosing one of the quick table calculations. Even when I'm doing a more sophisticated calculation, I start with a quick table calculation and then start editing.
If you are doing something like a moving average, the filter and the moving average can interact. For example, if I'm showing a 5 day trailing moving average over 30 day period, the first few days do not get averaged in the same way -- you don't have days over 30 days ago. If that's not really an issue for you, that's cool and you are done.
If it is an issue, it's going to be trickier. I'd suggest creating a second filter based on a table calc. The reason is the order of operations in Tableau. The raw data is filtered then aggregated by the database, then the table calcs are performed. If there are any filters on table calculations, then they are filtered after that. So basically, in my example, you want create a filter for 35 days on the date, then create a table calc on the date -- like using the INDEX() function. Filter the index function to show 30 days worth, then you've got a moving average that uses 35 days to compute the average, but only shows 30.

Different Aggregation calculations of a measure using two dimensions in Tableau

It is a Tableau 8.3 Desktop Edition question.
I am trying to aggregate data using two different dimensions. So, I want to aggregate twice: first I want to sum over all the rows and then multiply the results in a cummulative manner (so I can build a graph). How do I do that? Ok, too vague, here follow some more details:
I have a set of historical data. The columns are the date, the rows are the categories.
Easy part: I would like to sum all the rows.
Hard part: Given this those summations I want to build a graph that for each date it shows the product of all the summations from the earlier date till this date.
In another words:
Take the sum of all rows, call it x_i, where i is the date.
For each date i find y_i such that y_i = x_0 * x_1 * ... * x_i (if there is missing data, consider it to be one)
Then show a line graph for the y values versus the date.
I have searched for a solution for this and tried to figure it out by myself, but failed.
Thank you very much for your time and help :)
You need n calculated fields (number of columns you have), and manually do the calculation you need:
y_i = sum(field0)*sum(field1)
Basically because you cannot iterate on columns. For tableau, each column represent a different dimension or measure. So it won't consider that there is a logic order among them, meaning, it won't assume that column A comes before column B. It will assume A and B are different things.
Tableau works better with tables organized as databases. So if you have year columns, you should reorganize your data, eliminate all those columns and create a single field called 'Date', which will identify the value of your measure for that date. Yes, you will have less columns but far more rows. But Tableau works better this way (for very good reasons).
Tableau 9.0 allows you to do that directly. I only watched a demo (it was launched yesterday), but I understand that now there is an option to selected those columns (in the Data Connection tab) and convert them to a database format.
With that done, you can use a PREVIOUS_VALUE function to help you. I'm not with Tableau right now. As soon as I get to it I'll update this with the final answer . Unless you take the lead and discover yourself before that ;)

Tableau Draw Financial Data Series

I am new to tableau. I am just trying the simplest task: I want to draw a stock price time trend. I have data and I have price. But no matter how I tried, tableau seems no option for this raw data drawing-- you have to select a measure, whether sum or average or count but no option for just raw data. Can someone tell me how to do this? Thx!
Sum should be fine and as you add dimensions the granularity will be determined. For example, Take one of your stocks and add the date to columns and the symbol to rows. Most likely you want to see daily close price so right click and change to exact date. At this point the sum shouldn't matter because you should only have one price for each day in your record. If you have hourly price data, I would suggest using close price or change the date to the hour level.
In the Analysis menu uncheck aggregate measures, then no aggregations are performed on the measures and you see all the values.