When viewing sales history for a customer and looking at the trend for a period of time, I have noticed that the trend line can be misleading. The first example is in Domo, you can see that there were no purchases in Feb or Nov of 2017 for this customer. 
However, the trendline is very flat. If you were to include 0 for the two missing months, the trend line should look like this:
I have tried to graph using ifnull(`Net Test QTY`,0) but that did not change the trendline either.
Any suggestions?