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一般来说，我们二级分区表都会使用模版，如果没有使用模版特性，那么就会报ERROR: no partitions specified at depth 2类似的错误。因为没有模版，必须要显式指定分区。

当然我们在建表的时候，如果没有指定，那么后面也可以通过alter table 语句进行添加。下面我们通过一个例子看一下。

CREATE TABLE sales (trans_id integer,ctime timestamp without time zone,region text
)DISTRIBUTED BY (trans_id) PARTITION BY RANGE(ctime)SUBPARTITION BY LIST(region)(START ('2023-08-18 00:00:00'::timestamp without time zone) END ('2023-08-19 00:00:00'::timestamp without time zone) WITH (tablename='sales_1_prt_1', appendonly='false')(SUBPARTITION usa VALUES('usa') WITH (tablename='sales_1_prt_1_2_prt_usa', appendonly='false'),SUBPARTITION asia VALUES('asia') WITH (tablename='sales_1_prt_1_2_prt_asia', appendonly='false'),SUBPARTITION europe VALUES('europe') WITH (tablename='sales_1_prt_1_2_prt_europe', appendonly='false')));#如果只指定一级分区，添加分区会报错
alter table sales add partition sale_3  start (date '2023-08-20') inclusive end (date '2023-08-21') exclusive ;
NOTICE:  CREATE TABLE will create partition "sales_1_prt_sale_3" for table "sales"
ERROR:  no partitions specified at depth 2
#必须显式指定才可以添加成功
alter table sales add partition sale_2 
START ('2023-08-19 00:00:00'::timestamp without time zone) END ('2023-08-20 00:00:00'::timestamp without time zone) (SUBPARTITION usa VALUES('usa'),SUBPARTITION asia VALUES('asia') ,SUBPARTITION europe VALUES('europe') );
#插入一些测试数据
insert into sales select generate_series(1,10000000) ,current_date ,'usa';
insert into sales select generate_series(1,10000000) ,current_date ,'asia';
insert into sales select generate_series(1,10000000) ,current_date ,'europe';#添加模版，就算之前有历史数据，也是瞬间完成
ALTER TABLE sales
SET SUBPARTITION TEMPLATE(SUBPARTITION usa VALUES('usa') WITH (tablename='sales'),SUBPARTITION asia VALUES('asia') WITH (tablename='sales'),SUBPARTITION europe VALUES('europe') WITH (tablename='sales'))
;
NOTICE:  adding level 1 subpartition template specification for relation "sales"
NOTICE:  CREATE TABLE will create partition "sales_1_prt_subpartition_template" for table "sales"NOTICE:  CREATE TABLE will create partition "sales" for table "sales_1_prt_subpartition_template"
NOTICE:  CREATE TABLE will create partition "sales" for table "sales_1_prt_subpartition_template"
NOTICE:  CREATE TABLE will create partition "sales" for table "sales_1_prt_subpartition_template"
ALTER TABLE#这次只指定一级分区就可以添加成功
alter table sales  add partition sale_3  start (date '2023-08-20') inclusive end (date '2023-08-21') exclusive ;
NOTICE:  CREATE TABLE will create partition "sales_1_prt_sale_2" for table "sales"
NOTICE:  CREATE TABLE will create partition "sales_1_prt_sale_2_2_prt_usa" for table "sales_1_prt_sale_2"
NOTICE:  CREATE TABLE will create partition "sales_1_prt_sale_2_2_prt_asia" for table "sales_1_prt_sale_2"
NOTICE:  CREATE TABLE will create partition "sales_1_prt_sale_2_2_prt_europe" for table "sales_1_prt_sale_2"
ALTER TABLE

总结：
建表的时候，最好添加二级分区以后的模版，模版也可以后面变更，如果不加模版，添加分区的时候，必须指定子分区，所以分区级别越多，越复杂。