ApacheIoTDB在批量插入多个字段时如何查询最新值？
在IoTDB中，可以使用“HEADER;”语句定义表字段，然后使用“INSERT;”语句插入数据。在插入数据的同时，可以使用“SELECT LAST ()”来查询最新值。
下面是示例代码：
//定义表字段 String sql = "CREATE TIMESERIES root.sg.d1.s1 WITH DATATYPE=INT32, ENCODING=RLE;"; Statement statement = connection.createStatement(); statement.execute(sql);
//插入数据 String sql = "INSERT INTO root.sg.d1(timestamp,s1) VALUES (1509465600000,10),(1509465601000,20),(1509465602000,30),(1509465603000,40),(1509465604000,50)"; Statement statement = connection.createStatement(); statement.execute(sql);
//查询最新值 String sql = "SELECT LAST(s1) FROM root.sg.d1"; Statement statement = connection.createStatement(); ResultSet resultSet = statement.executeQuery(sql);
while(resultSet.next()){ ResultSetMetaData metaData = resultSet.getMetaData(); int columnCount = metaData.getColumnCount(); for (int i = 1; i <= columnCount; i++) { System.out.println(metaData.getColumnName(i) + " = " + resultSet.getString(i)); } }