最大值（COUNT（*））不起作用

Question

我有以下代码：

SELECT  e.Student_ID, s.Name, s.Surname, Result_IS, COUNT(*) 
FROM Students s 
LEFT JOIN Exams e
  ON e.Student_ID=s.Student_ID
WHERE Result_IS='Negative'
GROUP BY e.Student_ID, s.Name, s.Surname, Result_IS
HAVING COUNT(*)=
(
  SELECT MAX(COUNT(*)) FROM Exams
  WHERE Student_ID=e.Student_ID
    AND Result_IS='Negative'
  GROUP BY e.Student_ID, s.Name, s.Surname, Result_IS
) 

我遇到HAVING COUNT(*)的问题，COUNT(*)应选择package minesweeper; import javax.swing.JToggleButton; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; public class Mine extends javax.swing.JFrame { final int wid = 9,hei = 9,noOfbombs = 10; JToggleButton[][] blocks = new JToggleButton[hei][wid]; int[][] blox = new int[hei][wid]; ActionListener listen = new ActionListener() { public void actionPerformed(ActionEvent e){ int i = 0, j = 0; boolean found = false; for ( i = 0 ; i < hei ; i++) { for (j = 0 ; j < wid ; j++) { if (e.getSource() == blocks[i][j]) { found = true; break; } } if(found) break; } blocks[i][j].setText("Writing"); } }; public Mine() { initComponents(); for(int i = 0; i < hei ; i++) { for(int j = 0 ; j < wid;j++) { blocks[i][j] = new JToggleButton(); blocks[i][j].setSize(jPanel1.getWidth()/wid,jPanel1.getHeight()/hei); jPanel1.add(blocks[i][j]); blocks[i][j].setLocation(j*jPanel1.getWidth()/wid, i*jPanel1.getHeight()/hei); blocks[i][j].addActionListener(listen); } } } private void resiz(){ for(int i = 0;i<hei;i++) { for(int j = 0;j<wid;j++) { blocks[i][j] = new JToggleButton(); blocks[i][j].setSize(jPanel1.getWidth()/wid, jPanel1.getHeight()/hei); jPanel1.add(blocks[i][j]); blocks[i][j].setLocation(j*jPanel1.getWidth()/wid, i*jPanel1.getHeight()/hei); } } } // <editor-fold defaultstate="collapsed" desc="Generated Code"> private void initComponents() private void jPanel1ComponentResized(java.awt.event.ComponentEvent evt) { resiz(); } public static void main(String args[]) { //@override java.awt.EventQueue.invokeLater(new Runnable() { public void run() { new Mine().setVisible(true); } }); } // Variables declaration - do not modify private javax.swing.JPanel jPanel1; // End of variables declaration 给出最大结果的行，而只是给我第一个选择的输出，如下所示：

我一直在尝试各种各样的事情，但没有什么可以选择行，其中count是最大值。

请给我一个提示，请从哪里开始，以及代码有什么问题。

Answer 1

为什么不按count（*）desc排序并选择top 1？

SELECT top 1  e.Student_ID, s.Name, s.Surname, Result_IS, COUNT(*) FROM Students s LEFT JOIN Exams e
ON e.Student_ID=s.Student_ID
WHERE Result_IS='Negative'
GROUP BY e.Student_ID, s.Name, s.Surname, Result_IS
order by count(*) desc

我认为这是Oracle

的语法

  Select * FROM 
    (
            SELECT e.Student_ID, s.Name, s.Surname, Result_IS, COUNT(*) FROM Students s LEFT JOIN Exams e
            ON e.Student_ID=s.Student_ID
            WHERE Result_IS='Negative'
            GROUP BY e.Student_ID, s.Name, s.Surname, Result_IS
            order by count(*) desc
) 
    Where rownum=1

Answer 2

待办事项

HAVING COUNT(*)=
(
SELECT MAX(COUNT(*)) FROM Exams
WHERE Student_ID=e.Student_ID
AND Result_IS='Negative'
GROUP BY e.Student_ID, s.Name, s.Surname, Result_IS
)

查询已连接的表。 ：）

Answer 3

所以，我发现了如何做到，解决方案如下：

SELECT  e.Student_ID, s.Name, s.Surname, Result_IS, COUNT(*) FROM Students s LEFT JOIN Exams e
ON e.Student_ID=s.Student_ID
WHERE Result_IS='Negative'
GROUP BY e.Student_ID, s.Name, s.Surname, Result_IS
HAVING COUNT(*)=
(
SELECT MAX(count) from
(
SELECT count(*) as count FROM Exams
WHERE Result_Is='Negative'
GROUP BY Student_ID
) 
)