TL;DR: SQL is still a DE's best and most ubiquitous tool/language in the space--hands down.
I've led DE teams for the last decade. I have lived through shifts in toolsets, languages, etc. Regardless of platform, languages, model types, etc, etc, etc, etc, the one constant has been SQL with some sort of of scripting around it.
Right now, it seems Python is the big wrapper language, whether it's via dag or some other means but that's just the preferred method TODAY. Considering SQL has been around for decades and has outlasted just about every other language and system, many of which have opted for a SQL-like interface on top of their system, I would highly recommend DEs be very strong there.
I've led DE teams for the last decade. I have lived through shifts in toolsets, languages, etc. Regardless of platform, languages, model types, etc, etc, etc, etc, the one constant has been SQL with some sort of of scripting around it.
Right now, it seems Python is the big wrapper language, whether it's via dag or some other means but that's just the preferred method TODAY. Considering SQL has been around for decades and has outlasted just about every other language and system, many of which have opted for a SQL-like interface on top of their system, I would highly recommend DEs be very strong there.