java SQL参数问题Jdbc

Question

我从用户那里获取输入并存储在两个不同的变量中。我正在用sql语句绑定参数。当我运行代码时，它给出了连接查询部分的问题

String CityA= null;
String CityB= null;
try {
   CityA = readEntry(in, "Enter Origin City : ");
   CityB = readEntry(in, "Enter Destination City : ");

   // We treat this drop table specially to allow it to fail
   // as it will the very first time we run this program

  try {
  String q = "SELECT f.FLNO,f.DISTANCE,TIMEDIFF(f.arrives,f.departs) 
              as Duration FROM FLIGHTS F"
              + " WHERE F.ORIGIN = "+CityA;
              + "AND f.DESTINATION = "+CityB;

  System.out.println(q);
  rset = stmt.executeQuery(q);
  while (rset.next()) {
     System.out.println(rset.getInt("FLNO") + "," 
     + rset.getInt("Distance") + "," 
     + rset.getTime("Duration"));
  }
  System.out.println("Done");
  }
  catch (SQLException e) {
  // assume not there yet, so OK to continue
}        
finally {
        stmt.close(); 
}

Answer 1

请查找查询代码：- 基本上你错过了CityA和AND之间的空格

String q = "SELECT f.FLNO,f.DISTANCE,TIMEDIFF(f.arrives,f.departs) as Duration FROM FLIGHTS F"
                + " WHERE F.ORIGIN = '"+CityA+"' ";
                + "AND f.DESTINATION = '"+CityB+"'";

Answer 2

您的查询字符串中有一个输入错误-您错过了'Los-Angeles'和AND之间的空格