MySQL多个ORDER BY与UNION

Question

我想按日期获取数据。 我正在使用工会。

我已经浏览了以下网址。 但是我对此并没有明确的解决方案。

mysql order by union似乎不起作用

我的查询

(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 

我的结果

+-------+------+---------------------+
| 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 |
+-------+------+---------------------+

在上述网址中，日期顺序无效。 我不想像普通人那样下订单。 我需要为两个选择查询使用单独的顺序（在UNION中使用）。

更新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

上面给出了以下结果。

+-------+------+---------------------+
| 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 |
+-------+------+---------------------+

在此结果中，我不想对“ mid ”列进行重新排序

Answer 1

您需要包装两个select语句的并集结果，并按pdate对其进行排序。

如下：

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

我不确定为什么还需要union 。 而且，我不完全理解第三列的值应该是什么，因为它不是聚合函数的参数，也不在group by 。

但是，我将查询编写为：

(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;

笔记：

• 将子查询限制为10行。 为什么要处理比所需更多的数据？
• 在子查询之后使用ORDER BY对所有结果进行排序。
• 使用UNION ALL而不是UNION这样您的查询就不会产生删除重复项的开销。

Answer 3

再创建一列，以便可以对每个UNION查询进行排序

SQL小提琴演示

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

可以删除另外两个ORDER BY子句。 实际上很少有DB仅将ORDER BY OR LIMIT子句放在Union语句之前。 您可能要尝试以下操作：

    (
(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

尝试这个

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

固定仅按日期或组排序的日期

Answer 6

我使用临时表解决联合上的订购问题：

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