I want to create a hive dataset to extract only the row with a "dat_trt" >= system date - 2 days.
Which sql function I should use please.
While this is a Hive (and not DSS) question, you can refer to threads such as this one for some guidance and options. It seems it will depend on your Hive version of course.
You can try these things out in a Hive notebook in DSS as well.