Exception in thread "main" org.apache.flink.table.api.TableException: toAppendStream doesn't support consuming update changes which is produced by node GroupAggregate(groupBy=[amount, product, user], select=[amount, product, user])
解决方案:
tEnv.toAppendStream(result, Row.class).print(); env.execute();
改成:
tEnv.toRetractStream(result, Row.class).print(); env.execute();