def fetch_value(self, select, table_name, where=None, extra=None):
try:<EOL><INDENT>self.verify_table_existence(table_name)<EOL><DEDENT>except TableNotFoundError as e:<EOL><INDENT>logger.debug(e)<EOL>return None<EOL><DEDENT>result = self.execute_query(<EOL>Select(select, table_name, where, extra), logging.getLogger().findCaller()<EOL>)<EOL>if result is None:<EOL><INDENT>return None<EOL><DEDENT>fetch = result.fetchone()<EOL>if fetch is None:<EOL><INDENT>return None<EOL><DEDENT>return fetch[<NUM_LIT:0>]<EOL>
Fetch a value from the table. Return |None| if no value matches
the conditions, or the table not found in the database.

:param str select: Attribute for SELECT query
:param str table_name: Table name of executing the query.
:param where: |arg_select_where|
:type where: |arg_where_type|
:return: Result of execution of the query.
:raises simplesqlite.NullDatabaseConnectionError:
    |raises_check_connection|
:raises simplesqlite.OperationalError: |raises_operational_error|