Java 查询不返回输出
我正在编写一个程序,当用户使用单选按钮选择某个选项时,就会分配参数和sql语句:Java 查询不返回输出,java,mysql,netbeans,Java,Mysql,Netbeans,我正在编写一个程序,当用户使用单选按钮选择某个选项时,就会分配参数和sql语句: if(r1.isSelected())//SNo { cmd="SELECT * FROM CALLDETAILS WHERE SNo=?"; parameter=tf1.getText(); } else if(r2.isSelected())//Month-wise { cmd="SELECT SNO, DATE, COMPANY
if(r1.isSelected())//SNo
{
cmd="SELECT * FROM CALLDETAILS WHERE SNo=?";
parameter=tf1.getText();
}
else if(r2.isSelected())//Month-wise
{
cmd="SELECT SNO, DATE, COMPANY,STATUS FROM CALLDETAILS WHERE MONTH(DATE)=?";
parameter=tf1.getText();
}
else if(r2.isSelected())//Username
{
cmd="SELECT * FROM CALLDETAILS WHERE ATTENDED_BY=?";
parameter=tf1.getText();
}
else if(r3.isSelected())//Company
{
cmd="SELECT * FROM CALLDETAILS WHERE COMPANY=?";
parameter=tf1.getText();
}
else//Status
{
cmd="SELECT * FROM CALLDETAILS WHERE Status=?";//Resolved. in process, pending
parameter=tf1.getText();
}
当我运行此命令时:
try
{
Connection con=DriverManager.getConnection("jdbc:mysql://localhost/tenderdetails?user=root&password=");
PreparedStatement ps;
ps=con.prepareCall(cmd);
ps.setString(1,parameter);
ResultSet rs=ps.executeQuery();
while(rs.next())
{
int sno=rs.getInt(1);
Timestamp dt=rs.getTimestamp(2);
System.out.println(sno+ " "+dt);//HERE!
}
con.close();
System.out.println("here too");
}
catch(SQLException se)
{
JOptionPane.showMessageDialog(this, "Error: "+se.getMessage());
}
此处没有标记的语句的输出。为什么呢 你的陈述似乎不一定与你的想法一致
else if(r2.isSelected())//Month-wise // <-- r2
{
cmd="SELECT SNO, DATE, COMPANY,STATUS FROM CALLDETAILS WHERE MONTH(DATE)=?";
parameter=tf1.getText();
}
else if(r2.isSelected())//Username // <-- r2 again...? Won't ever be hit.
else if(r2.isSelected())///Month-wise//您的语句似乎不一定与您的想法一致
else if(r2.isSelected())//Month-wise // <-- r2
{
cmd="SELECT SNO, DATE, COMPANY,STATUS FROM CALLDETAILS WHERE MONTH(DATE)=?";
parameter=tf1.getText();
}
else if(r2.isSelected())//Username // <-- r2 again...? Won't ever be hit.
else if(r2.isSelected())//按月//检查getConnection()
字符串和您的查询/准备语句
因为它不返回任何结果,所以这里可能会出现问题。检查getConnection()
字符串和您的查询/准备语句
因为它不返回任何结果,所以这里可能会出现问题。因为SQL语句没有返回任何命中率…看起来您的查询没有返回任何东西(而循环根本没有执行)。是否引发异常?但我的数据库正在返回值,否则。。。在mysql服务器上。太好了,谢谢!getConnection解决了这个问题!XD因为您的SQL语句没有返回任何命中率…您的查询似乎没有返回任何东西(而循环根本没有执行)。是否引发异常?但我的数据库正在返回值,否则。。。在mysql服务器上。太好了,谢谢!getConnection解决了这个问题!xDI打算更改SELECT*。这只是为了让代码运行。我打算更改SELECT*。这只是为了让代码运行。