1  

Try this, Changes in query and in setting prepared statement parameters,

试试这个,查询中的更改以及设置预准备语句参数,

public int checkBetweenDates() throws SQLException{
        String t1 = "2015-07-08"; //or later some user input variable
        String t2 = "2015-07-09";//or later some user input variable
        String id = "22 03 E7 99";//or later some user input variable
        int rowCount = -1;
        //Statement stmt = null;        

        String dateChoice = "select count(*) " 
                + "from dancers " 
                + "where ts between ? and ?"
                + "AND id = ?";

        Connection conn = DriverManager.getConnection(host, username, password);
        System.out.println("Connected:");
         PreparedStatement preparedStmt = (PreparedStatement) conn.prepareStatement(dateChoice);
       preparedStmt.setString    (1, t1);
       preparedStmt.setString    (2, t2);
       preparedStmt.setString    (3, id);
        // stmt = conn.createStatement();
        ResultSet rs = preparedStmt.executeQuery(dateChoice); 
        try {
                rs = preparedStmt.executeQuery(dateChoice);
                rs.next();
                rowCount = rs.getInt(1);
                System.out.println(rowCount);
            }
         catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        finally {
            rs.close();
            preparedStmt.close();
        }
        return rowCount; 

    }

Share the exact error if doesn't work for you.

如果不适合您,请分享确切的错误。

0  

Change this:

String dateChoice = "select count(*) " 
            + "from dancers " 
            + "where ts between (t1) and (t2)"
            + "and id = (id)"
            + "values (?)";

According to the database syntax that you are using. For example if you using a webserver with Mysql go and type the query to see where the typo is. (if you using mysql it needs dancers to every table)

根据您使用的数据库语法。例如,如果您使用带有Mysql的Web服务器,请输入查询以查看拼写错误的位置。 (如果你使用mysql它需要每个表的舞者)

0  

First, you seem to have edited this method many times to try fix the problem, which has left it in a confused state.

首先,您似乎已多次编辑此方法以尝试修复问题,这使其处于混乱状态。

remove the "values (?)" from the sql statement, it does not belong here, it seems to be left over from a prepared insert statement.

从sql语句中删除“values(?)”,它不属于这里,它似乎是从一个准备好的insert语句中遗留下来的。

call preparedStmt.executeQuery() with zero arguments, you have already supplied it with the sql string and only call it ONCE, you assign a value to rs twice.

调用带有零参数的preparedStmt.executeQuery(),你已经为它提供了sql字符串并且只调用它ONCE,你为rs赋值两次。

your sql statement should contain exactly three question marks, try

你的sql语句应该包含三个问号,试试

select count(*) from dancers where ts between ? and ? and id = ?

next call preparedStmt.setString() three times to supply values t1, t2 and id.

接下来调用prepareStmt.setString()三次来提供值t1,t2和id。

Also, remember to close the connection object in the finally block.

另外,请记住在finally块中关闭连接对象。