MySQL查询错误SQLException

Question

I encountered this issue when trying to implement query requests into a program. Connecting to the database without this method works fine, however, this throws a SQLException .

    String query = "SELECT EXISTS ( SELECT * FROM usr WHERE username = admin AND password = pass )";
    boolean result;
    Connection con = null;
    try {
        con = DriverManager.getConnection(url, username, password);
        Statement stmt = (Statement) con.createStatement();
        ResultSet rs = stmt.executeQuery(query);
        result = rs.next();
    } catch (SQLException e) {
        throw new RuntimeException("Cannot connect to the database!", e);
    } finally {
        System.out.println("Closing the connection.");
        if (con != null)
            try {
                con.close();
            } catch (SQLException ignore) {
                System.out.println("Unknown Error Connecting to MySQL Server!");
            }
    }

I brought the query into the method to isolate it. Any help would be appreciated.

Answer 1

通常搜索字符串 - 您需要单引号值 - 因此在where子句中用'admin'和'pass'替换。