Microsoft® SQL Server 2008 R2 Unleashed

Managing User-Defined Function Permissions

When a function is initially created, the only user who has permission to execute the function is the user who created it. To allow other users to execute a scalar function, you need to grant EXECUTE permission on the function to the appropriate user(s), group(s), or role(s). For a table-valued function, you need to grant SELECT permission to the user(s), group(s), or role(s) that will need to reference it. The following example grants EXECUTE permission on the getonlydate() function to everyone and SELECT permission on the AveragePriceByType function to the database user fred:

For more detailed information ...