Question

您好我在Java中使用MySQL时遇到错误。每当我尝试插入到我的表中时（我在下面运行“testOne”时），我一直收到这个未知列错误。

public static void sendMessage(String username, String recipientName, String message, String title) {                
    DateFormat dateFormat = new SimpleDateFormat("yyyy:MM:dd HH:mm:ss");                
    Date date = new Date();                
    String stringDate = dateFormat.format(date);                
    String query = "INSERT INTO messages" + " (fromUser, toUser, message, title, dateCreated) VALUES ('" + 
    username + "', '" + recipientName + "', '" + message + "', '" + title + "', '" + stringDate + "')";                                   
    DBConnection.getInstance().executeQuery(query);                
}

public void testOne(){
    Message.sendMessage("user1", "user2", "hows it going", "hi");
}

CREATE TABLE messages (
    id int AUTO_INCREMENT,
    fromUser varchar(255),
    toUser varchar(255), 
    mType int,
    message TEXT,
    title TEXT,
    dateCreated varchar(255),
    seen TINYINT(1),
    quizID int,
    PRIMARY KEY(pID)
  );

public ResultSet executeQuery(String query){
    ResultSet rs= null;
    try {
        java.sql.Statement stmt = connection.createStatement();
        // this is the trick -- you need to pass different SQL to different methods
        if (query.startsWith("SELECT")) {
            rs = stmt.executeQuery(query);
        } else if (query.startsWith("UPDATE") || query.startsWith("INSERT")
                || query.startsWith("DELETE")) {
            stmt.executeUpdate(query, Statement.RETURN_GENERATED_KEYS);
            rs = stmt.getGeneratedKeys();
        } else {
            stmt.execute(query, Statement.RETURN_GENERATED_KEYS);
            rs = stmt.getGeneratedKeys();
        }
    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        return null;
    }
    return rs;
}

public static DBConnection getInstance() {
    if (instance == null)
        instance = new DBConnection(DBConnection.rootDirectory);
    return instance;
}

但每次运行测试时都会出现此错误 - “字段列表”中的“未知”列“消息” 请帮忙!!!

Answer 1

您收到错误的是哪一列？我面临着类似的问题。我在值“字符串”之前和之后放置了空格，并且它运行良好。在你的情况下，尝试在逗号之前添加空格。

“字段列表”中INSERT未知列的Mysql错误

1 个答案: