Several data centric widgets (i.e., Chart, Query, Filter) would benefit from the capability to insert a true SQL expression, rather than simply the expression builder option. An expression builder does not have the full capabilities needed. An example is that I have a feature layer of which contains a total acreage field of which I need to summarize (preferably in the Chart widget), but need the capability to summarize the minimum values of which duplicate records exist (for other reasons) and must be filtered to be unique records.
This applies to the Webapp Builder as well.