ORA-00911: invalid character
Remove ; (semi-colon) from the end of SQL string
Remove ; (semi-colon) from the end of SQL string
Remove single quotes around @username, and with respect to oracle use : with parameter name instead of @, like: OracleCommand oraCommand = new OracleCommand(“SELECT fullname FROM sup_sys.user_profile WHERE domain_user_name = :userName”, db); oraCommand.Parameters.Add(new OracleParameter(“userName”, domainUser)); Source: Using Parameters