I took a look at your workbook and the underlying data. The simplest way to get what you described will be to restructure your data. Putting all of the dates in one column, the Social Network in an other, and there respective values in a third. Then when you pull it into Tableau you bring the date to the Columns shelf, the values to the Rows shelf, and the Social Network to Color. That will give you one chart with all three networks and there impacts.
I have attached a workbook where I have structured the data this way so you can take a look at it.
Be careful, because of the different magnitudes of the data some of it may be hard to see when it is all on one chart.
AllSocialHelp.twbx 460.6 KB
I looked through your data and FB has oldest and newest date, then I used FB date as "Master" date.
You can start duplicating datasource x 2.
And link the date of LI and TW to FB(FB as master).
Final view looks like below.
duplicate data source x2
Edit relationships for each copied datasource respectively
Remove all existing relationships and only link with "date"
go back to primary datasource and put FB total reach
then from 2nd (LI) put Linked in clicks
then from 3rd one (TW) put Twitter Impressions
AllSocialHelp_rep_9.2.twbx 402.5 KB
Amazing. Got it. Thank you so much!
You are very welcome.
It is by luck that the [FaceBook Date] field
has min & max date values for the datasource.
If it's not, then a special "Scaffold" datasource
is needed to blend data into.
My other concern is about String-to-Date transformation
calculations in Tableau, such as DATE() or DATEPARSE().
Their results depend on a user computer locale (regional) settings.
As an example below is a screenshot of a view
as seen on my Mac OS X 10.10.1 with a Russian locale:
Note how LinkedIn data are blended "wrong" --
that's because of [LI DatePARSE] calculation
to give me NULLs instead of valid dates.
I definitely favor Peter's suggestion
to re-structure data to a better shape,
which is more convenient to analyze.
That's why I marked his answer as helpful.
Please find the attached wb and a Scaffold DS as well.
Thank you for following up, Yuriy