They are all close enough to similar. It's kind of like the difference between Scheme and Common Lisp. PL/SQL and T-SQL are different, but not so different as

They are all close enough to similar. It's kind of like the difference between Scheme and Common Lisp. PL/SQL and T-SQL are different, but not so different as to require a new way of thinking, for example. Of course, I've worked with lots of dialects of SQL fairly extensively, so I may be over-simplifying.