In my case I started to really learn sql on my current job, even the previous job I had was sql development for a year, this job exposed me to scripting, sp's, sql jobs and millions of lines of code. I also had the opportunity to learn from talented SQL developers. I really started to dive in deep 2 years in...The two most funnest aspects that I enjoy now are Nested sub-queries and quick de-duping using partition over.