??????????

[??????]

????????????????:  
??????fromElements??????????????????????????????????????????????????
??????????????????????????????????????????????
??????????
StreamExecutionEnvironment env = 
StreamExecutionEnvironment.getExecutionEnvironment();
StreamTableEnvironment tenv = StreamTableEnvironment.create(env);
env.setRuntimeMode(RuntimeExecutionMode.BATCH);  //????????????????

DataStreamSource<Tuple2<String, Integer&gt;&gt; source = 
env.fromElements(Tuple2.of("aa", 1),
        Tuple2.of("aa", 2),Tuple2.of("aa", 3),Tuple2.of("bb", 
2),Tuple2.of("bb", 3),Tuple2.of("bb", 4));
Table table = tenv.fromDataStream(source,
        Schema.newBuilder()
                .column("f0", "STRING")
                .column("f1", "INTEGER")
                .build());
tenv.createTemporaryView("test",table);
//????????sql????
tenv.createTemporarySystemFunction("Average", avg5.Average.class);
tenv.executeSql("SELECT f0,Average(f1) as rbm FROM test group by f0").print();

??????
+----+--------------------------------+--------------------------------+
| op |                             f0 |                            rbm |
+----+--------------------------------+--------------------------------+
| +I |                             aa | [0, 0, 0, 0, 1, 0, 0, 0, 0,... |
| -U |                             aa | [0, 0, 0, 0, 1, 0, 0, 0, 0,... |
| +U |                             aa | [0, 0, 0, 0, 1, 0, 0, 0, 0,... |
| -U |                             aa | [0, 0, 0, 0, 1, 0, 0, 0, 0,... |
| +U |                             aa | [0, 0, 0, 0, 1, 0, 0, 0, 0,... |
| +I |                             bb | [0, 0, 0, 0, 1, 0, 0, 0, 0,... |
| -U |                             bb | [0, 0, 0, 0, 1, 0, 0, 0, 0,... |
| +U |                             bb | [0, 0, 0, 0, 1, 0, 0, 0, 0,... |
| -U |                             bb | [0, 0, 0, 0, 1, 0, 0, 0, 0,... |
| +U |                             bb | [0, 0, 0, 0, 1, 0, 0, 0, 0,... |
+----+--------------------------------+--------------------------------+
??????????????????????????????????????????????????????

??????????????batch??????????????????????????????????????????????????????????????????

????????????????????????????????????????????????????????????????????????????????????????????????

??????


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