Ed Hansberry takes us through the data profiler in Power Query:
A solid green bar is usually best. It means there are no issues in that column, as shown in the Discounts field. On the far right in the COGS field, there is a tiny bit of gray. That means there is no data, or a null, in one or more records. The bigger the gray bar, the higher percentage of nulls there are. In the middle though we have a problem. Anything in red is an error and must be fixed. These may cause more errors in further transformations downstream, and will usually cause refresh errors.
Before we address this, let’s get a bit more information about our data. Go to the View ribbon, and there are 3 settings we want to look at.
I really like what the data profiler provides us. If you’re a regular Power BI user, I highly recommend checking it out if you haven’t already.