User-Defined Functions

User-defined functions are a class of procedures that return a single value to the calling environment.

• Creating User-Defined Functions
  Use the CREATE FUNCTION statement to create user-defined functions.
• Calling User-Defined Functions
  You can use user-defined functions, subject to permissions, in the same places you would use built-in nonaggregate functions.
• Dropping a user-defined function (SQL)
  User-defined functions remain in the database until they are explicitly removed.
• Permissions to Execute User-Defined Functions
  A user-defined function is owned by the user who created it; that user can execute it without permission.
• Granting the ability to execute a user-defined function (SQL)
  Grant the ability to execute a user-defined function by granting the EXECUTE object-level privilege.