Merge query result sets after fuzzy query and sorting

Today we need to make a query, the time of the day in descending order of the first, then the other in descending order of time after the time of the day.

SELECT * FROM
(SELECT * FROM Table
Where time like ' 2015-11-16% '
ORDER BY time Desc) a
UNION ALL SELECT * FROM
(SELECT * FROM Table
where ID not in
(Select Table.id from Table
Where time like ' 2015-11-12% ')
ORDER BY time Desc) b
Limit 0,20

Must be wrapped outside a layer, directly two result sets union found normal above, due in the following, but the internal is unordered, that is, the Union is not the order by the Union,

The internal order by does not take effect, the first layer should be produced by the Temporary intermediate table, the order is fixed.

Merge query result sets after fuzzy query and sorting