向范围分区表新增分区

例如，对范围分区表range_sales新增一个分区。

gaussdb=# CREATE TABLE range_sales
(
    product_id INT4 NOT NULL,
    customer_id INT4 NOT NULL,
    time DATE, channel_id CHAR(1),
    type_id INT4,
    quantity_sold NUMERIC(3),
    amount_sold NUMERIC(10,2)
)
PARTITION BY RANGE (time)
(
    PARTITION date_202001 VALUES LESS THAN ('2020-02-01'),
    PARTITION date_202002 VALUES LESS THAN ('2020-03-01'),
    PARTITION date_202003 VALUES LESS THAN ('2020-04-01'),
    PARTITION date_202004 VALUES LESS THAN ('2020-05-01')
);
gaussdb=# CREATE TABLESPACE tb1;
gaussdb=# ALTER TABLE range_sales ADD PARTITION date_202005 VALUES LESS THAN ('2020-06-01') TABLESPACE tb1;
gaussdb=# DROP TABLE range_sales;
gaussdb=# DROP TABLESPACE tb1;