I usually follow the below approach if the dataset is not too big and I don't have time to edit the load script:
Define two variables - vMinMonth & vMaxMonth
And in the chart, create a calculated dimension by using ValueLoop() and plug in the above variables:
In the expression, enter the below:
And finally the chart:
However, this approach has its own flaws. I am attaching the qvw if you are interested.
Other useful links by Sinan:
Populate Missing Dates.qvw 154.0 K