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使用MySQL编写语句？(Prepared statements with MySQL?)

 对于准备好的语句，我在语法方面遇到了一些麻烦。  
 我有以下代码  
String query2="SELECT lname FROM school_student WHERE sid = ? ORDER BY sid;";

PreparedStatement ps = cn.prepareStatement(query2);
ps.setInt(1, 3);
ResultSet rs = ps.executeQuery(query2);
 
 我遇到的问题是我收到此错误消息：  
 
  com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '? ORDER BY sid' at line 1  
 
 但是，当我替换“？” 在我的查询3中，查询工作正常，没有错误，并给我我想要的。 我如何设置“？”的值似乎有问题。 在我的查询？ 我使用了错误的语法吗？ 

I am having some trouble with, what I believe to by syntax, for prepared statements.  
I have the following code 
String query2="SELECT lname FROM school_student WHERE sid = ? ORDER BY sid;";

PreparedStatement ps = cn.prepareStatement(query2);
ps.setInt(1, 3);
ResultSet rs = ps.executeQuery(query2);
 
The problem I am having is that I am getting this error message: 
 
 com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '? ORDER BY sid' at line 1 
 
However, when I substitute the "?" in my query for a 3, the query works fine with no error and gives me what I want. There seems to be something wrong with how I am setting the value of the "?" in my query? Am I using the wrong syntax?

原文：https://stackoverflow.com/questions/15258425

更新时间：2023-05-05 18:05

最满意答案

 为了输入字段值已发布到您的后端，它无法禁用。 将其更改为只读并将其样式设置为看起来像已禁用：  
input[readonly] { 
    background: #CCC; 
    color: #333; 
    border: 1px solid #666 
}

In order to input field value was posted to your backend it cannot be disabled. Change it to readonly and style it to look like disabled: 
input[readonly] { 
    background: #CCC; 
    color: #333; 
    border: 1px solid #666 
}

使用MySQL编写语句？(Prepared statements with MySQL?)

最满意答案

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