It's a fundamentally different way of thinking.

With imperative programming, the mindset is: "I have this certain outcome in mind. What is the sequence of steps I need to take to make it happen?"

In a relational database, the mindset you need to be in is: "How can I define the relational structure of my world (i.e. my data) so that I can get the outcomes I want - and end up saving a great deal of imperative programming effort in the longer run?"

Quite different. And yes, it takes a while to get used to.