expressions.py 文件源码

def compile(self, side, compiler, connection):
        if not isinstance(side, DurationValue):
            try:
                output = side.output_field
            except FieldError:
                pass
            else:
                if output.get_internal_type() == 'DurationField':
                    sql, params = compiler.compile(side)
                    return connection.ops.format_for_duration_arithmetic(sql), params
        return compiler.compile(side)