一般來說，我們二級分區表都會使用模版，如果沒有使用模版特性，那么就會報ERROR: no partitions specified at depth 2類似的錯誤。因為沒有模版，必須要顯式指定分區。

當然我們在建表的時候，如果沒有指定，那么后面也可以通過alter table 語句進行添加。下面我們通過一個例子看一下。

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')));#如果只指定一級分區，添加分區會報錯
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
#必須顯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') );
#插入一些測試數據
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，就算之前有歷史數據，也是瞬間完成
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#這次只指定一級分區就可以添加成功
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

總結：
建表的時候，最好添加二級分區以后的模版，模版也可以后面變更，如果不加模版，添加分區的時候，必須指定子分區，所以分區級別越多，越復雜。