Mysql multiple ORDER BY with UNION

Question

I want to get data with order by date. I am using union.

I have gone through the below url. But I am not getting clear solution with that.

mysql order by with union doesn't seem to work

My Query

(SELECT n.nid, 
        Max(na.gid)                 AS mid, 
        fav.field_date_posted_value AS pdate 
 FROM   `node` AS n 
 JOIN nodeaccess AS na 
   ON na.nid = n.nid 
 LEFT JOIN field_data_field_date_posted AS fav 
        ON fav.entity_id = n.nid 
 WHERE  ( na.gid IN( 10, 11 ) 
          AND ( n.status = '1' ) 
          AND ( n.type IN ( 'article', 'blog', 'events', 'media', 
                            'press_releases', 'expert_speak', 'feature', 
                            'case_study', 
                            'news', 'the_igtb_series', 'trend', 'white_paper' ) 
              ) ) 
 GROUP  BY n.nid 
 ORDER  BY pdate DESC) 

UNION 

(SELECT n.nid, 
        Max(na.gid)                 AS mid, 
        fav.field_date_posted_value AS pdate 
 FROM   `node` AS n 
 JOIN nodeaccess AS na 
   ON na.nid = n.nid 
 LEFT JOIN field_data_field_date_posted AS fav 
        ON fav.entity_id = n.nid 
 WHERE  ( na.gid IN( 2 ) 
          AND ( n.status = '1' ) 
          AND ( n.type IN ( 'article', 'blog', 'events', 'media', 
                            'press_releases', 'expert_speak', 'feature', 
                            'case_study', 
                            'news', 'the_igtb_series', 'trend', 'white_paper' ) 
              ) ) 
 GROUP  BY n.nid 
 ORDER  BY pdate DESC) 
LIMIT 
10 

My Result

+-------+------+---------------------+
| nid   | mid  | pdate               |
+-------+------+---------------------+
| 12472 |   10 | 2015-05-11 00:00:00 |
| 12473 |   10 | 2015-04-03 00:00:00 |
| 12475 |   10 | 2015-06-08 00:00:00 |
| 12476 |   10 | 2015-12-15 01:55:48 |
| 12477 |   10 | 2014-06-30 00:00:00 |
| 12478 |   10 | 2013-12-26 00:00:00 |
| 12482 |   10 | 2014-02-02 00:00:00 |
| 12483 |   10 | 2014-09-01 00:00:00 |
| 12484 |   10 | 2015-12-04 00:00:00 |
| 12485 |   10 | 2015-08-14 00:00:00 |
+-------+------+---------------------+

In the above url the date order is not working. I don't want to make order by as common. I need separate order by for both select queries (Used in UNION).

Update 2:

(SELECT n.nid, max(na.gid) as mid, fav.field_date_posted_value as pdate FROM `node` as n
JOIN nodeaccess AS na ON na.nid = n.nid
LEFT JOIN field_data_field_date_posted AS fav ON fav.entity_id = n.nid
WHERE (na.gid IN(10,11) AND (n.status = '1') AND (n.type IN  ('article','blog', 'events', 'media', 'press_releases', 'expert_speak', 'feature', 'case_study', 'news', 'the_igtb_series', 'trend', 'white_paper')) )
GROUP BY n.nid 
ORDER BY pdate DESC)

UNION

(SELECT n.nid, max(na.gid) as mid, fav.field_date_posted_value as pdate FROM `node` as n
JOIN nodeaccess AS na ON na.nid = n.nid
LEFT JOIN field_data_field_date_posted AS fav ON fav.entity_id = n.nid
WHERE (na.gid IN(2) AND (n.status = '1') AND (n.type IN  ('article','blog', 'events', 'media', 'press_releases', 'expert_speak', 'feature', 'case_study', 'news', 'the_igtb_series', 'trend', 'white_paper')) )
GROUP BY n.nid 
ORDER BY pdate DESC)

ORDER BY pdate DESC LIMIT 10

The above gives the below result.

+-------+------+---------------------+
| nid   | mid  | pdate               |
+-------+------+---------------------+
| 12789 |   11 | 2016-09-26 00:00:00 |
| 12826 |    2 | 2016-07-13 00:00:00 |
| 12845 |    2 | 2016-07-05 00:00:00 |
| 12823 |   10 | 2016-06-21 00:00:00 |
| 12822 |    2 | 2016-06-17 00:00:00 |
| 12821 |   10 | 2016-06-07 00:00:00 |
| 12635 |   10 | 2016-06-07 00:00:00 |
| 12821 |    2 | 2016-06-07 00:00:00 |
| 12633 |   10 | 2016-05-25 02:19:29 |
| 12548 |   10 | 2016-05-20 00:00:00 |
+-------+------+---------------------+

In this result I don't want to reorder the column " mid "

Answer 1

You need to wrap the outcome of union of both select statements and order it by pdate .

as below:

SELECT * from 
    (
        (SELECT n.nid, max(na.gid) as mid, fav.field_date_posted_value as pdate FROM `node` as n
        JOIN nodeaccess AS na ON na.nid = n.nid
        LEFT JOIN field_data_field_date_posted AS fav ON fav.entity_id = n.nid
        WHERE (na.gid IN(10,11) AND (n.status = '1') AND (n.type IN  ('article','blog', 'events', 'media', 'press_releases', 'expert_speak', 'feature', 'case_study', 'news', 'the_igtb_series', 'trend', 'white_paper')) )
        GROUP BY n.nid 
        ORDER BY pdate DESC)

        UNION

        (SELECT n.nid, max(na.gid) as mid, fav.field_date_posted_value as pdate FROM `node` as n
        JOIN nodeaccess AS na ON na.nid = n.nid
        LEFT JOIN field_data_field_date_posted AS fav ON fav.entity_id = n.nid
        WHERE (na.gid IN(2) AND (n.status = '1') AND (n.type IN  ('article','blog', 'events', 'media', 'press_releases', 'expert_speak', 'feature', 'case_study', 'news', 'the_igtb_series', 'trend', 'white_paper')) )
        GROUP BY n.nid 
        ORDER BY pdate DESC)
    ) as UnionTable 
ORDER BY pdate DESC limit 10

Answer 2

I'm not sure why a union is even needed. And, I don't fully understand what the third column value is supposed to be, because it is not the argument to an aggregation function and is not in the group by .

However, I would write the query as:

(SELECT n.nid, max(na.gid) as mid, fav.field_date_posted_value as pdate
 FROM `node` n JOIN
      nodeaccess na
      ON na.nid = n.nid LEFT JOIN
      field_data_field_date_posted fav
      ON fav.entity_id = n.nid
 WHERE (na.gid IN(10,11) AND (n.status = '1') AND (n.type IN  ('article','blog', 'events', 'media', 'press_releases', 'expert_speak', 'feature', 'case_study', 'news', 'the_igtb_series', 'trend', 'white_paper')) )
 GROUP BY n.nid 
 ORDER BY pdate DESC
 LIMIT 10
) UNION ALL
(SELECT n.nid, max(na.gid) as mid, fav.field_date_posted_value as pdate
FROM `node` n JOIN
     nodeaccess na
     ON na.nid = n.nid LEFT JOIN
     field_data_field_date_posted fav
     ON fav.entity_id = n.nid
 WHERE (na.gid IN(2) AND (n.status = '1') AND (n.type IN  ('article','blog', 'events', 'media', 'press_releases', 'expert_speak', 'feature', 'case_study', 'news', 'the_igtb_series', 'trend', 'white_paper')) )
 GROUP BY n.nid 
 ORDER BY pdate DESC
 LIMIT 10
)
ORDER BY pdate DESC
LIMIT 10;

Notes:

• Limit the subqueries to 10 rows. Why bother processing more data than needed?
• Use an ORDER BY after the subqueries to order all the results.
• Use UNION ALL instead of UNION so your query does not incur the overhead of removing duplicates.

Answer 3

Create one additional column so you can order each UNION query

Sql Fiddle Demo

SELECT '1' as grp, 1 as ID
UNION 
SELECT '1' as grp, 3 as ID
UNION
SELECT '1' as grp, 2 as ID
UNION
SELECT '1' as grp, 5 as ID
UNION 
SELECT '2' as grp, 4 as ID
UNION 
SELECT '2' as grp, 7 as ID
UNION
SELECT '2' as grp, 2 as ID
UNION
SELECT '2' as grp, 5 as ID

ORDER BY grp, ID

OUTPUT

Answer 4

Two additional ORDER BY Clause can be removed. In fact few DB only to put ORDER BY OR LIMIT clause before Union statement. You might want to try below:

    (
(SELECT n.nid, max(na.gid) as mid, fav.field_date_posted_value as pdate FROM `node` as n
JOIN nodeaccess AS na ON na.nid = n.nid
LEFT JOIN field_data_field_date_posted AS fav ON fav.entity_id = n.nid
WHERE (na.gid IN(10,11) AND (n.status = '1') AND (n.type IN  ('article','blog', 'events', 'media', 'press_releases', 'expert_speak', 'feature', 'case_study', 'news', 'the_igtb_series', 'trend', 'white_paper')) )
GROUP BY n.nid 
 )

UNION

(SELECT n.nid, max(na.gid) as mid, fav.field_date_posted_value as pdate FROM `node` as n
JOIN nodeaccess AS na ON na.nid = n.nid
LEFT JOIN field_data_field_date_posted AS fav ON fav.entity_id = n.nid
WHERE (na.gid IN(2) AND (n.status = '1') AND (n.type IN  ('article','blog', 'events', 'media', 'press_releases', 'expert_speak', 'feature', 'case_study', 'news', 'the_igtb_series', 'trend', 'white_paper')) )
GROUP BY n.nid) 
) order by pdate DESC limit 10

Answer 5

Try this

SELECT n.nid, max(na.gid) as mid,fav.field_date_posted_value, UNIX_TIMESTAMP(fav.field_date_posted_value) as pdate, 1 as ob FROM `node` as n
JOIN nodeaccess AS na ON na.nid = n.nid
LEFT JOIN field_data_field_date_posted AS fav ON fav.entity_id = n.nid
WHERE (na.gid IN(10,11) AND (n.status = '1') AND (n.type IN  ('article','blog', 'events', 'media', 'press_releases', 'expert_speak', 'feature', 'case_study', 'news', 'the_igtb_series', 'trend', 'white_paper')) )
GROUP BY n.nid 


UNION ALL

SELECT n.nid, max(na.gid) as mid,fav.field_date_posted_value, UNIX_TIMESTAMP(fav.field_date_posted_value) as pdate, 2 as ob FROM `node` as n
JOIN nodeaccess AS na ON na.nid = n.nid
LEFT JOIN field_data_field_date_posted AS fav ON fav.entity_id = n.nid
WHERE (na.gid IN(2) AND (n.status = '1') AND (n.type IN  ('article','blog', 'events', 'media', 'press_releases', 'expert_speak', 'feature', 'case_study', 'news', 'the_igtb_series', 'trend', 'white_paper')) )
GROUP BY n.nid  

ORDER BY ob ASC, pdate DESC

Fixed the order by date only base or group

Answer 6

I use temporary tables to resolve ordering issues on union:

CREATE TEMPORARY TABLE IF NOT EXISTS temp_table1 AS 
(  
SELECT *   
FROM  table1   
ORDER BY < your specific order > )  

CREATE TEMPORARY TABLE IF NOT EXISTS temp_table2 AS 
(  
SELECT *   
FROM table2    
ORDER BY < your specific order > )  

SELECT * FROM temp_table1   
UNION ALL  
SELECT * FROM temp_table2