Yep, very nice kata. I had to refactor a number of times to make it work. Yet, in hindsight, the limit allows just enough variation in solutions to make this very well balanced, challenging and fun.

Thanks for the feedback! :)

SQL version is indeed different. Read the posts below, like this one: https://www.codewars.com/kata/5694cb0ec554589633000036/discuss#5e483169dd38d00015623356

There is nothing to guess:

You have to create the function factorial that receives n and returns n!.

You have to create the function factorial that receives n and returns n!

It says you have to return the factorial of n, or n! How is that not clear?

P.S.: I see you meant the SQL version, so you have a point there. Please mention the language you're talking about next time. There are some other posts about the same.