UDF and Stored Procedure
UDF : Excutable from SQL,SELECT and SQL action queries
SP :Use EXECUTE or EXEC to run
UDF : Doesnt return output parameters
SP : Supports output parameters
UDF : Returns table variable
SP : Can create a physical table and populate it, but cant return a table variable
UDF : Can join to a UDF
SP : Cant join to a SP
UDF : Cant make permanent changes to the server environment or an external source
SP : SP can be used to change some of the server environment and operiting environment
UDF : Cant be used in an XML FOR clause
SP : Can be used in an XML FOR clause
UDF : T-SQL errors stops the function when an error occurs
SP : Errors are ignored and T-SQL processes the next statement. Error handling code is to be done manually
UDF : User CREATE FUNCTION to create
SP : User CREATE PROCEDURE to create