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錯誤:javax.servlet.ServletException:值java.sql.SQLException:列 'NUM' 未找到
代碼:
<%
String driver = "com.mysql.jdbc.Driver";
Class.forName(driver).newInstance();
Connection con=null;
ResultSet rst=null;
ResultSet rst1=null;
ResultSet rst2=null;
ResultSet rst3=null;
Statement stmt=null;
Statement stmt1=null;
Statement stmt2=null;
Statement stmt3=null;
try{
String url="jdbc:mysql://localhost/company?user=root&password=root";
con=DriverManager.getConnection(url);
stmt=con.createStatement();
System.out.println("success");
}
catch(Exception e){
System.out.println(e.getMessage());
System.out.println("failed");
}
%>
<%
rst = stmt.executeQuery("select max(num) from invoicename;");
if (rst.next()) {
String str = rst.getString("num");
rst1 = stmt.executeQuery("Select sum(price) from invoices where invoiceno='" + str + "';");
if (rst1.next()) {
int s = rst1.getInt(1);
if (rst1.wasNull()) {
s = 0;
}
stmt.executeUpdate("insert into invoice values('" + str + "',curdate(),curtime(),'" + s + "');");
}
}
stmt.executeUpdate("insert into invoicename values();");
%>
錯誤:
javax.servlet.ServletException: java.sql.SQLException: Column 'num' not found
我無法在上面的代碼中找到問題。該錯誤已附加在圖像中。
請注意,這個問題的第一個版本是非常垃圾的,並且如果不關閉,它值得downvotes值得。請小心翼翼地寫下你的問題,避免txtspk和乞討。請注意,如果編寫真正的單詞太麻煩了,Stack Overflow可能不適合你。 – halfer