Factorial in SQL

Example for versions Microsoft SQL Server 2005

This example uses recursive factorial definition, implemented as a recursive query — a feature included in SQL Server 2005 and higher. Each row of recursive query contains two numeric fields — n and f = n!, and each row is calculated using the data of the previous row. 

with factorial(n, f) as
(
 select 0, 1
  union all
 select n+1, f*(n+1) from factorial where n<16
)
select cast(n as varchar)+'! = '+cast(f as varchar)
  from factorial