FlinkErr: Unknown call expression: sum(vc)

public class OverWindowTableApiTest {
    public static void main(String[] args) throws Exception {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(1);
        StreamTableEnvironment tableEnv = StreamTableEnvironment.create(env);

        DataStreamSource<String> streamSource = env.socketTextStream("hadoop102", 7777);
        SingleOutputStreamOperator<WaterSensor> map = streamSource.map(new MapFunction<String, WaterSensor>() {
            @Override
            public WaterSensor map(String value) throws Exception {
                String[] splits = value.split(",");

                WaterSensor waterSensor = new WaterSensor(splits[0], Long.valueOf(splits[1]), Integer.valueOf(splits[2]));
                return waterSensor;
            }
        });


        // 流转表（指定表结构）
        Schema schema = Schema.newBuilder()
                .column("id", "STRING")
                .column("ts", "BIGINT")
                .column("vc", "INT")
                .columnByExpression("pt" , "PROCTIME()")
                .columnByExpression("et", "TO_TIMESTAMP_LTZ(ts, 3)")
                //.watermark("et" , "source_watermark()") // 沿用流中的水位线
                .watermark("et" , "et - INTERVAL '1' SECOND ") // 重新定义水位线
                .build();
        Table table = tableEnv.fromDataStream(map, schema);

        // API式开窗
        OverWindow w1 = Over.partitionBy($("id")).orderBy($("pt")).preceding(UNBOUNDED_ROW).following(CURRENT_ROW).as("w");

        table.window(w1)
                .select(
                    $("id"), $("ts"), $("vc"), $("et"), $("vc").sum().over($("w")).as("sum_vc")
        ).execute().print();

        env.execute();
    }
}

再次运行

成功！