Singing and Playing the Bass

How might it compare to singing and guitar playing or drumming or piano playing?  Anyway, some popular people bass playing/singing are Sting and Geddy Lee.  Do you feel what they do is challenging?

All of this is based on how well you know how to play the instrument and the song in question.

What I mean by how well you know the instrument, I just mean anything higher than beginner.

Of course, singing and playing the bass isn't going to be difficult probably with easy basslines. Well, do you consider basslines by Rush and The Police to be hard? Well, the singing sections of Rush songs are probably a lot less complex than the non-singing parts, but I could be wrong.

I’m not that well versed on Rush songs to give an answer

I could be wrong. It seems like Rush songs are complex beginning to end