FlinkSQL DISTRIBUTEBY

FlinkSQL新增DISTRIBUTEBY特性，根据指定的字段进行分区，支持单字段及多字段，解决数据仅需要分区的场景。示例如下：

SELECT /*+ DISTRIBUTEBY('id') */ id, name FROM t1;
SELECT /*+ DISTRIBUTEBY('id', 'name') */ id, name FROM t1;
SELECT /*+ DISTRIBUTEBY('id1') */ id as id1, name FROM t1;