Oracle无效标识符不理解字符串 [英] Oracle invalid identifier doesnt understand string

问题描述

我的查询无法解决问题。这是命令变量。

I'm having an issue with my query not working. This is the command variable.

当它执行时，它应该检索具有BSc作为其学位的元组。我已经在oracle中直接测试了这个，查询返回了这些。它与命令语句相同。

When it executes it should be retrieving the tuples that have BSc as their degree. I have tested this in oracle directly and the query returns these. It is identical to the command statement.

当我打印出命令时，该行与我在oracle中运行的命令完全相同。

When I print out command, the line looks exactly the same as my command that worked in oracle.

SELECT distinct fname，lname，student_id FROM student where degree ='BA';

然而，它应该打印到屏幕上。这些表已经加载到oracle中了。

Yet, it should be printing out to the screen. The tables are loaded into oracle already.

我一直在用这个问题绞尽脑汁但似乎无法找到解决办法！

I've been racking my brain with this issue but can't seem to find a fix!

我一直得到的错误是：
ORA-00911：无效字符

The error I keep getting is: ORA-00911: invalid character

我所做的是将度存储在扫描仪的结果中，这是一个字符串。因此，在命令变量中连接它不应该产生问题 - 查询看起来与oracle中的相同。

What I do is I store in degree the result from scanner which is a string. So concatenating it in the command variable shouldn't make an issue -- the query looks identical to what works in oracle.

可能是因为它想要一个字符而不是一个字符串？如果确实如此，那我怎么能让它把BSc作为一个炭？连接字符听起来很愚蠢。

Could it be because it wants a char instead of a string? If it does, then how would I get it to make "BSc" as a char? Concatenating chars sounds dumb.

下面的相关代码：

 private String getDegree() {
  Scanner scan = new Scanner(System.in);
  System.out.println("Please enter degree code (either BA or BSc)");
  return scan.next();

}

//get the degree name
        String degree = getDegree();


        //get statement and execute appropriate select
        Statement stmt = con.createStatement();
        String command = "SELECT distinct fname, lname, student_id FROM student"+
           " where degree='"+ degree + "';";
        System.out.println(command);
        ResultSet result = stmt.executeQuery(command);

        //determine number of columns
        ResultSetMetaData metadata = result.getMetaData();
        int columns = metadata.getColumnCount();

        //print heading
        System.out.println("\nFNAME        LNAME         STUD_ID");
        System.out.println("====================================");

        //loop through result and print columns

        while (result.next()){
           for (int i=1; i <=columns; i++){
              System.out.print(result.getString(i)+spaces(15-result.getString(i).length()));
           }
           System.out.println();
        }

`

推荐答案

在JDBC中，您的SQL语句不应以分号结束。

In JDBC your SQL statement should not be terminated by semicolon.

更改

String command = "SELECT distinct fname, lname, student_id FROM student"+
       " where degree='"+ degree + "';";

到

String command = "SELECT distinct fname, lname, student_id FROM student"+
       " where degree='"+ degree + "'";

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