SQL Functions - factorial

Question

I am a beginner in SQL Functions. What is the best way to create a function for factorial in SQL Server- Say 10!

Answer 1

You asked which is the best way to create a function for factorial in SQL Server. As always, that depends on the context. But if you truly mean it in the generic sense, where performance matters, the best way to go is without a doubt to implement it as a CLR user-defined function.

https://docs.microsoft.com/en-us/sql/relational-databases/clr-integration-database-objects-user-defined-functions/clr-user-defined-functions?view=sql-server-2017

You can of course implement the function itself in whatever language you fancy. And a long/bigint doesn't really cut it for a factorial function (a bigint can only fit up to 20!, 21! is arithmetic overflow).