Question

我在查询中使用了此方法而没有使用连接，并且它按预期工作。但是我添加了一个内连接，现在它无法更新＆＃34;使用过的＆＃34;柱

  public HashMap<String, Comparable> getPhoneNumberAndMarkAsUsed() {
    String[] colNames = { "phone_number.id", "phone_number.phone_number",
        "phone_number.account_id", "phone_number.used AS used",
        "(now() AT TIME ZONE account.timezone)::time AS local_time" };
    String query = "select " + Stream.of(colNames).collect(Collectors.joining(", "))
        + " from account INNER JOIN phone_number ON account.id = phone_number.account_id where phone_number.used = false order by id DESC limit 1 for update";

    HashMap<String, Comparable> account = new HashMap<String, Comparable>();

    try (Connection conn = DriverManager.getConnection(url, props); // Make sure conn.setAutoCommit(false);
        Statement stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
        ResultSet rs = stmt.executeQuery(query)) {
      conn.setAutoCommit(false);

      ResultSetMetaData rsmd = rs.getMetaData();
      int columnsNumber = rsmd.getColumnCount();
      while (rs.next()) {

        for (int i = 1; i <= columnsNumber; i++) {
          if (i > 1)
            System.out.print(",  ");
          String columnValue = rs.getString(i);
          System.out.print(columnValue + " " + rsmd.getColumnName(i));
        }

        // Get the current values, if you need them.
        account.put("phone_number", rs.getString("phone_number"));
        account.put("account_id", rs.getLong("account_id"));

        rs.updateBoolean("used", true);
        rs.updateRow();
      }
      conn.commit();
    } catch (SQLException e) {
      e.printStackTrace();
    }

    return account;
  }

循环打印以下

7223 id,  10001234567 phone_number,  1093629 account_id,  f used,  23:32:42.502472 local_time

按照上面的输出，然后我使用那个列＆＃34;使用＆＃34;是ResultSet的一部分。但我得到以下例外

org.postgresql.util.PSQLException: ERROR: column "used" of relation "account" does not exist

这是打印时的查询

select phone_number.id, phone_number.phone_number, phone_number.account_id, phone_number.used AS used, (now() AT TIME ZONE account.timezone)::time AS local_time from account INNER JOIN phone_number ON account.id = phone_number.account_id where phone_number.used = false order by id DESC limit 1 for update

used属于phone_number表，而不属于account表。怎么解决这个问题？

Answer 1

这是代码中的问题：

rs.updateBoolean("used", true);

此语句将尝试通过结果集更新表的数据，但为此，您无法用户加入，也存在一个问题。当您通过结果集进行更新时，它将尝试更新帐户表，如果我们发现使用的列是帐户表，则会发生错误。

因此您的代码正在尝试查找列＆＃34;使用＆＃34;在帐户表中，但它不存在。

试试这个：

String query = "select " + Stream.of(colNames).collect(Collectors.joining(", "))
        + " from phone_number INNER JOIN account phone_number ON account.id = phone_number.account_id where phone_number.used = false order by id DESC limit 1 for update";

sql for update＆＃34; ERROR：column＆＃34; used＆＃34;关系＆＃34;帐户＆＃34;不存在＆＃34;即使它确实

1 个答案: