java - 查询在 SQL*Plus 上运行但不在 jdbc 程序中运行

Question

我在 sqlplus (Oracle 11g) 上执行了查询

select Bookdetails.TITLE,Bookdetails.PRICE
from bookdetails
inner join orderdetails
ON BOOKDETAILS.BOOKID=ORDERDETAILS.BOOKID
Where Orderdetails.username ='Divya.grg';

我得到了这个输出:

TITLE                                                             PRICE
------------------------------------------------------------ ----------
mastering c++                                                     876.2
construction material reference book 2nd edition                    332
let us c++                                                          793

但是当我在 JDBC 程序上执行相同的查询时:

PreparedStatement ps=conn.prepareStatement("select Bookdetails.TITLE,Bookdetails.PRICE"
  +"from bookdetails"
  +"inner join orderdetails"
  +"ON BOOKDETAILS.BOOKID=ORDERDETAILS.BOOKID"
  +"Where Orderdetails.username ='"+username+"'");
ResultSet rs=ps.executeQuery();

我收到此异常:

>java.sql.SQLSyntaxErrorException: ORA-00923: FROM keyword not found where expected

为什么会发生这种情况？如果 sqlplus 执行此操作没有任何问题，那么为什么会在程序中抛出异常？

Answer 1

在您要连接的行的开头放置空格以在 Java 中创建查询，否则您要连接的行将一起运行查询，如下所示:

select Bookdetails.TITLE,Bookdetails.PRICEfrom bookdetailsinner join orderdetails...

当你想要的时候

select Bookdetails.TITLE,Bookdetails.PRICE from bookdetails inner join orderdetails...