2-axis line chart in Google Sheets

Question

I've set up a Google Sheets to compare one set of statistics against another. The statistics are for traffic vs. an action. The actions only happen once a day and not every day whereas the traffic has more volume and happens every day.

What I want to show is a 2-line line chart with two axes so that I can run the two lines against one another. At the moment all I've been able to make is a chart with two lines, but both using the same axis. This means that the action line always is sitting at either 0 or 1, whereas the traffic line is going up to 30 but they are both drawn against the same axis so you can't really read the chart well to see a coloration.

I've linked a copy of the Google Sheets and a mock-up of what I'm trying to achieve here:

Answer 1

What you need to do is a few steps:

1. Insert to Chart then add your Data Series, as you normally would with a Single Axis chart.
2. (Optional) Change chart type to Line. You can change it to anything else later. Line seems to be a safe bet for the later options to appear. Not sure if this step is by Google design...
3. Right-click on the chart and select Series.
4. Change Apply Series to whichever Data Series you want to move to the Second Axis.
5. Change Axis to Right Axis.
6. Now you can go back to Chart type to make it a scatter, or bar, or anything else - the program will remember the Axis assigned to the Data Series, regardless of whatever options may be available.

tldr; the Google Support answer is broken for a few chart types. Do your Axis assignments with Line charts, and change the Chart Type after.

Answer 2

I don't see how your example image relates to your example data because with your data I get:

but at least the above shows a secondary vertical axis is possible (though only for certain chart types) and it did seem necessary to replace the blanks in your ColumnC with 0.

Answer 3

You can eliminate the need to replace blanks by going into Chart editor, Customize, Chart style, and enable Plot null values.