how to select with group by order by and desc?

Question

i want to select the data in a table such that it should group it by userid except one value in that column and order by date time and desc. The problem i am getting is the grouped items are not ordering by date and time and in desc manner. I mean the grouped item is showing earlier row. How can i do that. This is what i have done.

SELECT * FROM `tbljobs`
   GROUP BY user_id
   UNION ALL 
     SELECT * FROM tbljobs
     WHERE user_id = '1'
     ORDER BY date_time DESC
     LIMIT 20"

where '1' is should not be grouped.

Answer 1

Your ORDER BY is only executed on the second statement. You have to use braces to order the whole results:

(SELECT *
FROM `tbljobs`
GROUP BY user_id)
UNION ALL 
(SELECT *
FROM tbljobs
WHERE user_id = '1')
ORDER BY date_time DESC

Answer 2

Thank you friends for your suggestions. Finally I created the solution by myself after a lot of effort.

(
 SELECT * 
 FROM (
       SELECT * 
       FROM tbljobs 
       ORDER BY date_time desc 
      ) AS A 
 WHERE user_id <> '1' group by user_id 
) 
UNION ALL 
(
 SELECT * 
 FROM tbljobs 
 WHERE user_id=1
) 
ORDER BY date_time DESC