Looking for a little help understanding what the Where clause of this SQL query is doing. This is used to define a query layer in an ArcPro map. DBMS is postgresql
a.id, a.valid_date, a.id, a.name, a.net, a.elevation, a.mph, a.local_time, a.shape
obs.gusts AS a
I understand that the last line is a cast function, but I do not understand what the "r" represents and how it's filtering the data.
Thanks in advance