I was helping a user on http://community.powerbi.com this week. The user had a list of service desk tickets for multiple customers and the requirement was to identify when a customer opened a second new ticket within 7 days of closing a previous ticket. This is not an uncommon scenario so I thought it would make a good blog article.
One of the challenges that new users have when using Power BI is to decide if they should use Power Pivot (DAX modelling) or Power Query (PQL shaping) to solve each problem. And if the answer is DAX, then they also need to decide if it should be a measure or calculated column. There is no one single correct answer to these questions and it always depends on the circumstances. I generally recommend to shape your data properly prior to loading to Power Pivot, that way the DAX formulas are easier to write and the reporting database will be more performant. I looked at the options for this problem and decided to use Power Query to shape the data before loading. Power Pivot and DAX are not really designed to do ordinal row comparisons, so this task is better handled with Power Query.
For this particular problem I thought I would produce a video that demonstrates one way in which this problem can be solved. Here it is.
My Online Power Query Video Training
One of my new year’s resolutions was to baton down and create an online Power Query training course. This has been on my to-do list for almost 2 years now and I am well under way. The video above is a sample of my video course. I start from the beginning and walk the viewer through the foundation skills they need to know to be a Power Query guru. Towards the end of the course I will have a stack of videos like the one above where you can broaden your awareness of how you can use your new skills in real world situations. If you would like to sign up and be notified once the course is finished (no obligation), then please enter your contact details in the form below.
If you want a comprehensive lesson on how to use Power Query, checkout my training course here http://xbi.com.au/pqt