Question

我已编写以下代码（摘录）：

conn = Pooling.getDataSource().getConnection();
String databaseName = Configuration.getDatabaseName();
String sql = "SELECT * FROM " + databaseName + ".companies WHERE companyemail = ? AND companypassword = MD5(?)"; 
PreparedStatement prepStat = conn.prepareStatement(sql);
prepStat.setString(1, username);
prepStat.setString(2, password);
System.out.println("LoginService: prepStat = " + prepStat.toString());
ResultSet rs = prepStat.executeQuery(sql);
...

现在，当我执行此操作时，我获得了MySQLSyntaxErrorException。 prepStat.toString()打印：

SELECT * FROM dbname.companies WHERE companyemail = 'comp@comp.com' AND companypassword = MD5('passwort')

对SequelPro的简单复制和粘贴成功返回结果。

但是，后端仍然声称语法中存在错误：

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 '? AND companypassword = MD5(?)' at line 1

也许我是盲人，但我没有看到错误？但是这里发生了什么？

Answer 1

好的，我发现了问题所在。我用过：

ResultSet rs = prepStat.executeQuery(sql);

但是，我应该使用

ResultSet rs = prepStat.executeQuery();

代替。

Answer 2

试试这个：

String sql = "SELECT * FROM '" + databaseName + ".companies' WHERE companyemail=? AND companypassword = MD5(?)";

注意databaseName变量之前和.companies之后的单引号。我认为这可能是问题所在。

或者你可以这样做：

String sql = "SELECT * FROM ? WHERE companyemail =? AND companypassword = MD5(?)"; 
PreparedStatement prepStat = conn.prepareStatement(sql);
prepStat.setString(1, databaseName);
prepStat.setString(2, username);
prepStat.setString(3, password);

我认为问题在于将databaseName解析为准备好的语句。

PreparedStatement执行说MySQLSyntaxErrorException虽然在MySQL控制台中有效

2 个答案: