I’m trying to figure out how to create rolling 7 day periods. I have horizontal bar charts that are currently grouped by week, but I actually want them to be grouped by 7 day periods instead.
I used the Superstore data as an example. The top row in this image should be the last 7 days, with the latest date being in the top right, and so forth. Is this possible?
You can create a field to use as a dimension for this assuming you choose some anchor date to specify the beginning of a 7-day period. For this example, I’ll choose a literal date of July 4, 1776 but you could use the Today() function or the min or max transaction date in your data or whatever you like.
Then the DIV() and DATEDIFF() functions are all you need to calculate the number of 7 day periods Between the anchor date and the period containing [Order Date].
DIV(DATEDIFF('day', #7/4/1776#, [Order Date]), 7)
You’ll typically want to treat this field as a discrete dimension.
In the example below, I called the field [Period] and also displayed the earliest and latest dates found in the data for each Period.
In a more production oriented example, you may want to hide the header for the Period field and instead calculate the start/end dates for periods rather than draw them from the data, so that they show correctly if there were period boundaries without any transactions.
The formula to compute the [Period Start] is DATE(DATEADD('day', [Period] * 7, #7/4/1776#)) and to compute [Period End] is DATE(DATEADD('day', [Period] * 7 + 6, #7/4/1776#)) If you are going to use the anchor date in many formulas, it would be convenient to define it in one place with a parameter or calculated field.
Related
I want to plot a couple of measures by months over the last three years. The plot would be divided by year. So I put year and month for columns and the measure values for rows. The year is defined as DATEPART('year', [Month Date]) and month is DATEPART('month', [Month Date]).
The plot looks like this.
The lines are broken between years. Both YEAR and MONTH are blue (discrete), but if I change them to green (continuous), the lines are connected but it looks weird.
I wonder how to make continuous lines across year?
What has happened is you have converted a date part (i.e. Month = March) to a continuous unit. What this does is simply changes March to 3. This looses the context of what the actual date is (i.e. March 2007). To change this right click on the date field on the column. You will see two separate areas to format the dates i.e. there are two years (2015, 2015), two quarters (Q2 and Q2 2015) etc. The first is a date part and the second is truncated date from the original date/timestamp.
You want to change the format to the second Month option (Month May 2015) and ensure the data type is continuous.
This should give you a continuous line across the year. If not screenshot me where you get to and I can assist from there.
Check if the last week and first of the next year is the same, I have a similar issue and solved it by passing the dates as Day-Month-Year.
I have a chart that shows the number of departures for a given 15 minute interval as seen here.
I need to compound these counts backwards for one hour. For example, the 3 departures shown at 11:00 need to also be represented at the 10:00, 10:15, 10:30, and 10:45 columns. When completed, the 10:00 would have a total of 6 departures (10:15 -> 6, 10:30 ->5, 10:45 -> 4, 11:00 -> 4).
I have done this via VBA in excell, but am now needing to replicate the chart in Tableau and have been beating my head in for about two weeks now. I'd love to hear any and all suggestions.
You can use a Cartesian join against a large enough date range of your choosing to in effect resample your data and add the additional time intervals you desire.
For example, if you have a month's worth of data (min date -> max date = 30 days), then you have (30 * 24 * 4) 2880 15 minute intervals.
Create all those intervals in a separate data sheet
Add a bogus column with value of link for all rows
Create the same bogus in your actual data source
Join the two sheets together on the link column
Create a calculated field that is something along the following:
[Interval] <= [Flight Time] AND [Interval] >= DATEADD('hour',-1,[Flight Time])
This calculated field will evaluate to TRUE when the interval time is within one hour before the flight time. You can then drag this field onto your filter shelf and select TRUE value only. Effectively your [Interval] field becomes your new date field.
I would recommend adding that filter to the context and applying across the entire datasource. Before you add this filter you'll have 2880 times the about of data so be sure to do a live view first. Be careful with extracts using Cartesian joins as you could potentially be extracting more than you bargained for.
See the following links for different techniques on how to do this and re-sampling dates in general in tableau.
https://community.tableau.com/thread/151387
Depending on the size of your data (and if a live view is not necessary) it is often times easier and more efficient to do this type of pre-processing outside of tableau in SQL or something like python's pandas library.
Here is another solution provided from the Tableau Cumunity Forum. I have not tried tyvich's solution yet, but I know this one got me where I needed. Please follow the link to see the solution using moving table calculations.
https://community.tableau.com/thread/251154
In Tableau, I have a Date Filter with 31 days (days in a month).
I have a calculation,
Sum(sales)/(No of days)
Based on no of days selected in the Date Filter, my calculation should change.
Eg : If 12 days are selected in filter
The Calculation should be Sum(sales)/12
If 20 days then Sum(sales)/20.
Regards
Try this formula
sum(Sales) / datediff('day', min(Date), max(Date))
Just realize that if you have missing data at the start or end of your period, say no entries at all for the first few days of the month, it will only start counting days at the very first day of data, i.e. min(Date)
For those reasons, it is often useful to pad your data to have at least one row per day, even if it most of the fields are null in the padded data row. You can use a union or left join to do that without disturbing your original data.
I have a few years of data by day that looks like this:
Date Count
1/1/2015 1000
1/2/2015 1010
1/3/2015 1040
I would like to create a calculation that allows me to switch between Day, Month and Year using Tableau's date formats without having to calculate the average for each individual format. For instance, the monthly average for Jan 2015 would be the total of Count for all 31 days in January 2015 divided by 31.
Since you have no missing data (days) and no duplicate data, the solution is extremely easy.
Place the Count field on any shelf (except the filter shelf). For example, place it on the Rows shelf. Click on the Count field on the Rows shelf and change the aggregation to AVG(). You should see the AVG(Count) of all your data rows at this point.
Place the Date field on any shelf (except the filter shelf). For example, place it on the Columns shelf. Click on the Date field pill on the Columns shelf, and choose the level of granularity you wish from the SECOND batch of choices. (The first batch returns date parts, not dates) For example, choose Month. You'll see the Avg(Count) per month.
Place any other dimensions on shelves to either filter to specific dimension values or to show the average counts broken down by your other dimensions.
Users can drill up or down the granularity of your dates by clicking the + or - icons by the date axis, or by clicking on the Date pill. You can choose to display the dates as a continuous or discrete value.
If you don't like the +/- UI, then you can create a string valued parameter with values: year, quarter, month, day etc, and then create a calculated field using the date_trunc() function to allow, say, a dashboard user to to choose the date granularity from a different type of UI control.
I have a dataset as follows:
DATE | AMOUNT | CATEGORY
20.12.2015 | 100.00 | Drinks
22.12.2015 | 50.00 | Food
20.12.2015 | 70.00 | Transport
07.12.2015 | 50.00 | Transport
...
There are several records with amounts spent per week and day.
I would like to have a bar chart with the categories on the left and the length of the bars indicating the weekly average, ie. what is spent on average per week during a filtered time frame
If I user the normal AVG([AMOUNT]) it calculates the daily average, rather than the weekly one.
I found this question:
Tableau - weekly average from daily data
However one of the answers is not dynamically, the other lists averages for consecutive weeks, rather than per category and I can't think of a way to apply the same technique for mmy problem.
Add a new dimension, which is for the weeks
You can then create a variable which calculates the average amount for a specific week as follows:
{FIXED [Date (Week numbers)], [Category]: avg([Amount]) }
Then when you want to average you can average the above formula
AVG({FIXED [Date (Week numbers)], [Category]: avg([Amount]) })
First make sure the data type for the field named DATE is type date instead of string. If not, change the data type from the right mouse menu or worst case use the date parse function in a calculated field.
Second, after you place the DATE field onto a shelf, set the date level of granularity to Week. Again ], use the right mouse context menu. Choose from the second batch of choices to truncate dates to the week level. The first batch of options on that menu are date parts, not dates. You may want to then change the field to discrete depending on your intended view.
Based on Mark Andersen's solution I found the following:
create a calculated field WeekNumber:
DATETRUNC('week', [Date])
create a calculated field WeekTotal:
{FIXED [WeekNumber], [Main Category]: SUM([Amount Person]) }
create a calculated field WeekDiff:
DATEDIFF('week',#2015-08-01#,TODAY())
create a calculated field WeekAvg:
[WeekTotal] / [WeekDiff]
Use WeekAvg as the meassure for the bars and it's done.
A few remarks for that:
Mark's solution went int he right direction. I had to replace avg([Amount]) with sum([Amount]) since I want to have the total per week and average it afterwards.
However it didn't exactly calculate what I wanted since Tableau only calculates averages based on the weeks that have a spending.
If I have
40$ in week 1
20$ in week 2
30$ in week 4
then it calculates (40+20+30)/3 = 30 while I would like to have (40+20+30)/4 = 20.25
In my use case my solution works because I have a fixed time frame until TODAY(), however it would be conviniant if that would be calculated automatically if I use a filter between two arbitrary dates.