User defined Functions- Limitations and Restrictions

• User-defined functions cannot be used to perform actions that modify the database state.
• User-defined functions cannot contain an OUTPUT INTO clause that has a table as its target.
• User-defined functions cannot return multiple result sets. Use a stored procedure if you need to return multiple result sets.
• Error handling is restricted in a user-defined function. A UDF does not support TRY…CATCH, @ERROR or RAISERROR.
• User-defined functions cannot call a stored procedure, but can call an extended stored procedure.
• User-defined functions cannot make use of dynamic SQL or temp tables. Table variables are allowed.
• SET statements are not allowed in a user-defined function.