Sql function to get the max value from @temp table

Hi,

 

  Need to build one function by pass parameters and create one temp temp inside that to store fetched values and finally return the max of column values from that temp table as output

 

EX:

 

   fn_test (@P1,@P2)

   declare @temp (val 1, val 2)

   insert into @temp (1,2)

   insert into @temp (3,4)  

   select max(val1) from @temp -- as output and return 

 

Thanks

Sathish