Question

我希望按日期顺序获取数据。我正在使用工会。

我已经浏览了下面的网址。但我没有得到明确的解决方案。

mysql order by with union doesn't seem to work

我的查询

import java.awt.*;
import java.util.List;
import java.util.ArrayList;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.*;
import javax.swing.table.*;

public class TableComboBoxByRow extends JPanel
{
    List<String[]> editorData = new ArrayList<String[]>(3);

    public TableComboBoxByRow()
    {
        setLayout( new BorderLayout() );

        // Create the editorData to be used for each row

        editorData.add( new String[]{ "Red", "Blue", "Green" } );
        editorData.add( new String[]{ "Circle", "Square", "Triangle" } );
        editorData.add( new String[]{ "Apple", "Orange", "Banana" } );

        //  Create the table with default data

        Object[][] data =
        {
            {"Color", "Red"},
            {"Shape", "Square"},
            {"Fruit", "Banana"},
            {"Plain", "Text"}
        };
        String[] columnNames = {"Type","Value"};

        DefaultTableModel model = new DefaultTableModel(data, columnNames);
        JTable table = new JTable(model)
        {
            //  Determine editor to be used by row
            public TableCellEditor getCellEditor(int row, int column)
            {
                int modelColumn = convertColumnIndexToModel( column );

                if (modelColumn == 1 && row < 3)
                {
                    JComboBox<String> comboBox1 = new JComboBox<String>( editorData.get(row));
                    return new DefaultCellEditor( comboBox1 );
                }
                else
                    return super.getCellEditor(row, column);
            }
        };

        JScrollPane scrollPane = new JScrollPane( table );
        add( scrollPane );
//      table.getColumnModel().getColumn(1).setCellRenderer(new ComboBoxRenderer2() );
    }
/*
    class ComboBoxRenderer2 extends DefaultTableCellRenderer
    {
        @Override
        public Component getTableCellRendererComponent(
            JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column)
        {
            JLabel label = (JLabel) super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
            label.setIcon(UIManager.getIcon("Table.descendingSortIcon"));
            return label;
        }
    }
*/
    private static void createAndShowUI()
    {
        JFrame frame = new JFrame("Table Combo Box by Row");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add( new TableComboBoxByRow() );
        frame.setSize(200, 200);
        frame.setLocationByPlatform( true );
        frame.setVisible( true );
    }

    public static void main(String[] args)
    {
        EventQueue.invokeLater(new Runnable()
        {
            public void run()
            {
                createAndShowUI();
            }
        });
    }
}

我的结果

(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

在上面的网址中，日期顺序无效。我不想像普通人那样订购。对于两个选择查询，我需要单独的order by（在UNION中使用）。

更新2：

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

以上给出了以下结果。

(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

在此结果中，我不想重新排列“ mid ”

列

Answer 1

您需要包含两个select语句的union的结果，并按pdate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

我不确定为什么甚至需要union。并且，我不完全理解第三列值应该是什么，因为它不是聚合函数的参数而不在group by中。

但是，我会将查询编写为：

(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;

注意：

将子查询限制为10行。为什么要处理超出需要的数据呢？
在子查询后使用ORDER BY订购所有结果。
使用UNION ALL代替UNION，这样您的查询就不会产生删除重复项的开销。

Answer 3

创建一个附加列，以便您可以订购每个UNION查询

<强> 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

<强>输出

Answer 4

可以删除另外两个ORDER BY子句。实际上很少有DB只能在Union语句之前放置ORDER BY OR LIMIT子句。您可能想尝试以下内容：

    (
(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

试试这个

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

修正了按日期排序的基数或组

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

与UNION的Mysql多个ORDER BY

6 个答案: