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v2.1

Documentation:v2.1

Supported Versions:
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v3.1/
v3.0/
v2.1

Other Versions:
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v1.1

CREATE TABLE SUBPARTITION

Function

Creates a level-2 partitioned table. A partitioned table is a logical table that is divided into several physical partitions for storage based on a specific plan. A partitioned table is a logical table and does not store data. Data is stored in physical partitions. For a level-2 partitioned table, the top-level node table and level-1 partitioned table are logical tables and do not store data. Only the level-2 partitioned (leaf node) stores data.

The partitioning solution of a level-2 partitioned table is a combination of the partitioning solutions of two level-1 partitions. For details about the partitioning solution of a level-1 partitioned table, see CREATE TABLE PARTITION.

Common combination solutions for level-2 partitioned tables include range-range partitioning, range-list partitioning, range-hash partitioning, list-range partitioning, list-list partitioning, list-hash partitioning. Currently, level-2 partitioned tables can only be row-store tables.

Precautions

  • A level-2 partitioned table has two partition keys, and each partition key supports only one column.
  • If the constraint key of the unique constraint and primary key constraint contains all partition keys, a local index is created for the constraints. Otherwise, a global index is created.
  • The number of level-2 partitions (leaf nodes) in a level-2 partitioned table cannot exceed 1048575. The number of level-1 partitions cannot exceed 64, and there must be at least one level-2 partition under a level-1 partition.
  • Level-2 partitioned tables support only row store and do not support column-store, segment-page, or hash bucket.
  • UPSERT and MERGE INTO into are not supported.
  • When specifying a partition for query, for example, select * from tablename partition/subpartition (partitionname), ensure that the keywords partition and subpartition are correct. If they are incorrect, an error is reported during the query. In this case, the query is performed based on the table alias.
  • Level-2 partitioned tables do not support the subpartition for (values) query, for example, select * from tablename subpartition for (values).
  • Does not support secret database, ledger database and row-level access control.
  • Does not support subpartitions under INTERVAL partitions.

Syntax

CreateTableSubpartition ::= CREATE TABLE [ IF NOT EXISTS ] subpartition_table_name
( 
{ column_name data_type [ COLLATE collation ] [ column_constraint [ ... ] ]
| table_constraint
| LIKE source_table [ like_option [...] ] }[,... ]
)
[ AUTO_INCREMENT [ = ] value ]
[ WITH ( {storage_parameter = value} [,... ] ) ]
[ COMPRESS | NOCOMPRESS ]
[ TABLESPACE tablespace_name ]
PARTITION BY {RANGE [ COLUMNS ] | LIST [ COLUMNS ] | HASH | KEY} ( partition_key ) [ PARTITIONS integer ] SUBPARTITION BY {RANGE | LIST | HASH | KEY} ( subpartition_key ) [ SUBPARTITIONS integer ]
(
  { PARTITION partition_name1 [ VALUES LESS THAN { ( val1 ) | MAXVALUE} | VALUES [ IN ] ( val1 [,...]) ] [ TABLESPACE [=] tablespace ]
  (
       { SUBPARTITION subpartition_name1 [ VALUES LESS THAN ( val1_1 ) | VALUES ( val1_1 [,...])]  [ TABLESPACE [=] tablespace ] [COMMENT =? 'text' ] } [,...]
  ) } [,...]
)[ { ENABLE | DISABLE } ROW MOVEMENT ]

  • Column constraint:

    column_constraint ::= [ CONSTRAINT constraint_name ]
{ NOT NULL |
  NULL |
  CHECK ( expression ) |
  DEFAULT default_e xpr |
  GENERATED ALWAYS AS ( generation_expr ) STORED |
  UNIQUE index_parameters |
  PRIMARY KEY index_parameters |
  REFERENCES reftable [ ( refcolumn ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
        [ ON DELETE action ] [ ON UPDATE action ] }
[ DEFERRABLE | NOT DEFERRABLE | INITIALLY DEFERRED | INITIALLY IMMEDIATE ]

  • Table constraint:

    table_constraint ::= [ CONSTRAINT constraint_name ]
{ CHECK ( expression ) |
  UNIQUE ( column_name [, ... ] ) index_parameters |
  PRIMARY KEY ( column_name [, ... ] ) index_parameters |
  FOREIGN KEY ( column_name [, ... ] ) REFERENCES reftable [ ( refcolumn [, ... ] ) ]
      [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] [ ON DELETE action ] [ ON UPDATE action ] }
[ DEFERRABLE | NOT DEFERRABLE | INITIALLY DEFERRED | INITIALLY IMMEDIATE ]

  • LIKE options:

    like_option ::= { INCLUDING | EXCLUDING } { DEFAULTS | GENERATED | CONSTRAINTS | INDEXES | STORAGE | COMMENTS | RELOPTIONS| ALL }

  • Index parameters:

    index_parameters ::= [ WITH ( {storage_parameter = value} [, ... ] ) ]
[ USING INDEX TABLESPACE tablespace_name ]

Parameter Description

  • IF NOT EXISTS

    Does not throw an error if a relationship with the same name existed. A notice is issued in this case.

  • subpartition_table_name

    Specifies the name of a level-2 partitioned table.

    Value range: a string. It must comply with the identifier naming convention.

  • column_name

    Specifies the name of a column to be created in the new table.

    Value range: a string. It must comply with the identifier naming convention.

  • data_type

    Specifies the data type of the column.

  • COLLATE collation

    Assigns a collation to the column (which must be of a collatable data type). If no collation is specified, the default collation is used. You can run the select * from pg_collation; command to query collation rules from the pg_collation system catalog. The default collation rule is the row starting with default in the query result.

  • CONSTRAINT constraint_name

    Specifies the name of a column or table constraint. The optional constraint clauses specify constraints that new or updated rows must satisfy for an INSERT or UPDATE operation to succeed.

    There are two ways to define constraints:

    • A column constraint is defined as part of a column definition, and it is bound to a particular column.
    • A table constraint is not bound to a particular column and can apply to more than one column.

  • LIKE source_table [ like_option … ]

The secondary partition table does not support this function temporarily.

  • WITH ( storage_parameter [= value] [, … ] )

    Specifies an optional storage parameter for a table or an index. Optional parameters are as follows:

    • FILLFACTOR

      The fill factor of a table is a percentage from 10 to 100. 100 (complete filling) is the default value. When a smaller fill factor is specified, INSERT operations fill table pages only to the indicated percentage. The remaining space on each page is reserved for updating rows on that page. This gives UPDATE a chance to place the updated copy of a row on the same page, which is more efficient than placing it on a different page. For a table whose entries are never updated, setting the fill factor to 100 (complete filling) is the best choice, but in heavily updated tables a smaller fill factor would be appropriate. The parameter has no meaning for column-store tables.

      Value range: 10-100

    • ORIENTATION

      Determines the data storage mode of the table.

      Value range:

      • COLUMN: The data will be stored in columns.

      • ROW (default value): The data will be stored in rows.

      img NOTICE: ORIENTATION cannot be modified.

    • COMPRESSION

      • Value range: LOW, MIDDLE, HIGH, YES, and NO for column-store tables, with compression level increasing in ascending order. The default value is LOW.
      • Row-store tables cannot be compressed.

    • MAX_BATCHROW

      Specifies the maximum number of records in a storage unit during data loading. The parameter is only valid for column-store tables.

      Value range: 10000 to 60000. The default value is 60000.

    • PARTIAL_CLUSTER_ROWS

      Specifies the number of records to be partially clustered for storage during data loading. The parameter is only valid for column-store tables.

      Value range: greater than or equal to MAX_BATCHROW. You are advised to set this parameter to an integer multiple of MAX_BATCHROW.

    • DELTAROW_THRESHOLD

      A reserved parameter. The parameter is only valid for column-store tables.

      Value range: 0 to 9999

  • COMPRESS / NOCOMPRESS

    Specifies keyword COMPRESS during the creation of a table, so that the compression feature is triggered in case of BULK INSERT operations. If this feature is enabled, a scan is performed for all tuple data within the page to generate a dictionary and then the tuple data is compressed and stored. If NOCOMPRESS is specified, the table is not compressed. Row-store tables cannot be compressed.

    Default value: NOCOMPRESS, that is, tuple data is not compressed before storage.

  • TABLESPACE tablespace_name

    Specifies that the new table will be created in the tablespace_name tablespace. If the tablespace is not specified, the default tablespace is used.

  • PARTITION BY {RANGE | LIST | HASH} (partition_key)

    • For partition_key, the partitioning policy supports only one column of partition keys.
    • The data types supported by the partition key are the same as those supported by the level-1 partitioned table.

  • SUBPARTITION BY {RANGE | LIST | HASH} ( subpartition_key )

    • For subpartition_key, the partitioning policy supports only one column of partition keys.
    • The data types supported by the partition key are the same as those supported by the level-1 partitioned table.

  • { ENABLE | DISABLE } ROW MOVEMENT

    Specifies whether to enable row movement.

    If the tuple value is updated on the partition key during the UPDATE operation, the partition where the tuple is located is altered. Setting this parameter enables error messages to be reported or movement of the tuple between partitions.

    Value range:

    • ENABLE (default value): Row movement is enabled.
    • DISABLE: Row movement is disabled.

  • NOT NULL

    The column is not allowed to contain null values. ENABLE can be omitted.

  • NULL

    Indicates that the column is allowed to contain NULL values. This is the default setting.

    This clause is only provided for compatibility with non-standard SQL databases. It is not recommended.

  • CHECK (condition) [ NO INHERIT ]

    Specifies an expression producing a Boolean result where the INSERT or UPDATE operation of new or updated rows can succeed only when the expression result is TRUE or UNKNOWN; otherwise, an error is thrown and the database is not altered.

    A check constraint specified as a column constraint should reference only the column's values, while an expression in a table constraint can reference multiple columns.

    A constraint marked with NO INHERIT will not propagate to child tables.

    ENABLE can be omitted.

  • DEFAULT default_expr

    Assigns a default data value to a column. The value can be any variable-free expressions. (Subqueries and cross-references to other columns in the current table are not allowed.) The data type of the default expression must match that of the column.

    The default expression will be used in any INSERT operation that does not specify a value for the column. If there is no default value for a column, then the default value is NULL.

  • GENERATED ALWAYS AS ( generation_expr ) STORED

    This clause creates a column as a generated column. The value of the generated column is calculated by generation_expr when data is written (inserted or updated). STORED indicates that the value of the generated column is stored as a common column.

    img NOTE:

    • The generation expression cannot refer to data other than the current row in any way. The generation expression cannot reference other generation columns or system columns. The generation expression cannot return a result set. No subquery, aggregate function, or window function can be used. The function called by the generation expression can only be an immutable function.
    • Default values cannot be specified for generated columns.
    • The generated column cannot be used as a part of the partition key.
    • Do not specify the generated column and the CASCADE, SET NULL, and SET DEFAULT actions of the ON UPDATE constraint at the same time. Do not specify the generated column and the SET NULL, and SET DEFAULT actions of the ON DELETE constraint at the same time.
    • The method of modifying and deleting generated columns is the same as that of common columns. Delete the common column that the generated column depends on. The generated column is automatically deleted. The type of the column on which the generated column depends cannot be changed.
    • The generated column cannot be directly written. In the INSERT or UPDATE statement, values cannot be specified for generated columns, but the keyword DEFAULT can be specified.
    • The permission control for generated columns is the same as that for common columns.
    • Columns cannot be generated for column-store tables and MOTs. In foreign tables, only postgres_fdw supports generated columns.

  • UNIQUE index_parameters

    UNIQUE ( column_name [, … ] ) index_parameters

    Specifies that a group of one or more columns of a table can contain only unique values.

    For the purpose of a unique constraint, null is not considered equal.

  • PRIMARY KEY index_parameters

    PRIMARY KEY ( column_name [, … ] ) index_parameters

    Specifies that a column or columns of a table can contain only unique (non-duplicate) and non-NULL values.

    Only one primary key can be specified for a table.

  • DEFERRABLE | NOT DEFERRABLE

    They determine whether the constraint is deferrable. A constraint that is not deferrable will be checked immediately after every command. Checking of constraints that are deferrable can be postponed until the end of the transaction using the SET CONSTRAINTS command. NOT DEFERRABLE is the default value. Currently, only UNIQUE constraints, primary key constraints, and foreign key constraints accept this clause. All the other constraints are not deferrable.

  • INITIALLY IMMEDIATE | INITIALLY DEFERRED

    If a constraint is deferrable, this clause specifies the default time to check the constraint.

    • If the constraint is INITIALLY IMMEDIATE (default value), it is checked after each statement.

    • If the constraint is INITIALLY DEFERRED, it is checked only at the end of the transaction.

      The constraint check time can be altered using the SET CONSTRAINTS statement.

  • USING INDEX TABLESPACE tablespace_name

    Allows selection of the tablespace in which the index associated with a UNIQUE or PRIMARY KEY constraint will be created. If not specified, the index is created in default_tablespace. If default_tablespace is empty, the default tablespace of the database is used.

Examples

  • Example 1: Create level-2 partitioned tables of various combination types.

    CREATE TABLE list_list
(
    month_code VARCHAR2 ( 30 ) NOT NULL ,
    dept_code  VARCHAR2 ( 30 ) NOT NULL ,
    user_no    VARCHAR2 ( 30 ) NOT NULL ,
    sales_amt  int
)
PARTITION BY LIST (month_code) SUBPARTITION BY LIST (dept_code)
(
  PARTITION p_201901 VALUES ( '201902' )
  (
    SUBPARTITION p_201901_a VALUES ( '1' ),
    SUBPARTITION p_201901_b VALUES ( '2' )
  ),
  PARTITION p_201902 VALUES ( '201903' )
  (
    SUBPARTITION p_201902_a VALUES ( '1' ),
    SUBPARTITION p_201902_b VALUES ( '2' )
  )
);
insert into list_list values('201902', '1', '1', 1);
insert into list_list values('201902', '2', '1', 1);
insert into list_list values('201902', '1', '1', 1);
insert into list_list values('201903', '2', '1', 1);
insert into list_list values('201903', '1', '1', 1);
insert into list_list values('201903', '2', '1', 1);
select * from list_list;
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201903     | 2         | 1       |         1
 201903     | 2         | 1       |         1
 201903     | 1         | 1       |         1
 201902     | 2         | 1       |         1
 201902     | 1         | 1       |         1
 201902     | 1         | 1       |         1
(6 rows)

drop table list_list;
CREATE TABLE list_hash
(
    month_code VARCHAR2 ( 30 ) NOT NULL ,
    dept_code  VARCHAR2 ( 30 ) NOT NULL ,
    user_no    VARCHAR2 ( 30 ) NOT NULL ,
    sales_amt  int
)
PARTITION BY LIST (month_code) SUBPARTITION BY HASH (dept_code)
(
  PARTITION p_201901 VALUES ( '201902' )
  (
    SUBPARTITION p_201901_a,
    SUBPARTITION p_201901_b
  ),
  PARTITION p_201902 VALUES ( '201903' )
  (
    SUBPARTITION p_201902_a,
    SUBPARTITION p_201902_b
  )
);
insert into list_hash values('201902', '1', '1', 1);
insert into list_hash values('201902', '2', '1', 1);
insert into list_hash values('201902', '3', '1', 1);
insert into list_hash values('201903', '4', '1', 1);
insert into list_hash values('201903', '5', '1', 1);
insert into list_hash values('201903', '6', '1', 1);
select * from list_hash;
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201903     | 4         | 1       |         1
 201903     | 5         | 1       |         1
 201903     | 6         | 1       |         1
 201902     | 2         | 1       |         1
 201902     | 3         | 1       |         1
 201902     | 1         | 1       |         1
(6 rows)

drop table list_hash;
CREATE TABLE list_range
(
    month_code VARCHAR2 ( 30 ) NOT NULL ,
    dept_code  VARCHAR2 ( 30 ) NOT NULL ,
    user_no    VARCHAR2 ( 30 ) NOT NULL ,
    sales_amt  int
)
PARTITION BY LIST (month_code) SUBPARTITION BY RANGE (dept_code)
(
  PARTITION p_201901 VALUES ( '201902' )
  (
    SUBPARTITION p_201901_a values less than ('4'),
    SUBPARTITION p_201901_b values less than ('6')
  ),
  PARTITION p_201902 VALUES ( '201903' )
  (
    SUBPARTITION p_201902_a values less than ('3'),
    SUBPARTITION p_201902_b values less than ('6')
  )
);
insert into list_range values('201902', '1', '1', 1);
insert into list_range values('201902', '2', '1', 1);
insert into list_range values('201902', '3', '1', 1);
insert into list_range values('201903', '4', '1', 1);
insert into list_range values('201903', '5', '1', 1);
insert into list_range values('201903', '6', '1', 1);
ERROR:  inserted partition key does not map to any table partition
select * from list_range;
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201903     | 4         | 1       |         1
 201903     | 5         | 1       |         1
 201902     | 1         | 1       |         1
 201902     | 2         | 1       |         1
 201902     | 3         | 1       |         1
(5 rows)

drop table list_range;
CREATE TABLE range_list
(
    month_code VARCHAR2 ( 30 ) NOT NULL ,
    dept_code  VARCHAR2 ( 30 ) NOT NULL ,
    user_no    VARCHAR2 ( 30 ) NOT NULL ,
    sales_amt  int
)
PARTITION BY RANGE (month_code) SUBPARTITION BY LIST (dept_code)
(
  PARTITION p_201901 VALUES LESS THAN( '201903' )
  (
    SUBPARTITION p_201901_a values ('1'),
    SUBPARTITION p_201901_b values ('2')
  ),
  PARTITION p_201902 VALUES LESS THAN( '201904' )
  (
    SUBPARTITION p_201902_a values ('1'),
    SUBPARTITION p_201902_b values ('2')
  )
);
insert into range_list values('201902', '1', '1', 1);
insert into range_list values('201902', '2', '1', 1);
insert into range_list values('201902', '1', '1', 1);
insert into range_list values('201903', '2', '1', 1);
insert into range_list values('201903', '1', '1', 1);
insert into range_list values('201903', '2', '1', 1);
select * from range_list;
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201902     | 2         | 1       |         1
 201902     | 1         | 1       |         1
 201902     | 1         | 1       |         1
 201903     | 2         | 1       |         1
 201903     | 2         | 1       |         1
 201903     | 1         | 1       |         1
(6 rows)

drop table range_list;
CREATE TABLE range_hash
(
    month_code VARCHAR2 ( 30 ) NOT NULL ,
    dept_code  VARCHAR2 ( 30 ) NOT NULL ,
    user_no    VARCHAR2 ( 30 ) NOT NULL ,
    sales_amt  int
)
PARTITION BY RANGE (month_code) SUBPARTITION BY HASH (dept_code)
(
  PARTITION p_201901 VALUES LESS THAN( '201903' )
  (
    SUBPARTITION p_201901_a,
    SUBPARTITION p_201901_b
  ),
  PARTITION p_201902 VALUES LESS THAN( '201904' )
  (
    SUBPARTITION p_201902_a,
    SUBPARTITION p_201902_b
  )
);
insert into range_hash values('201902', '1', '1', 1);
insert into range_hash values('201902', '2', '1', 1);
insert into range_hash values('201902', '1', '1', 1);
insert into range_hash values('201903', '2', '1', 1);
insert into range_hash values('201903', '1', '1', 1);
insert into range_hash values('201903', '2', '1', 1);
select * from range_hash;
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201902     | 2         | 1       |         1
 201902     | 1         | 1       |         1
 201902     | 1         | 1       |         1
 201903     | 2         | 1       |         1
 201903     | 2         | 1       |         1
 201903     | 1         | 1       |         1
(6 rows)

drop table range_hash;
CREATE TABLE range_range
(
    month_code VARCHAR2 ( 30 ) NOT NULL ,
    dept_code  VARCHAR2 ( 30 ) NOT NULL ,
    user_no    VARCHAR2 ( 30 ) NOT NULL ,
    sales_amt  int
)
PARTITION BY RANGE (month_code) SUBPARTITION BY RANGE (dept_code)
(
  PARTITION p_201901 VALUES LESS THAN( '201903' )
  (
    SUBPARTITION p_201901_a VALUES LESS THAN( '2' ),
    SUBPARTITION p_201901_b VALUES LESS THAN( '3' )
  ),
  PARTITION p_201902 VALUES LESS THAN( '201904' )
  (
    SUBPARTITION p_201902_a VALUES LESS THAN( '2' ),
    SUBPARTITION p_201902_b VALUES LESS THAN( '3' )
  )
);
insert into range_range values('201902', '1', '1', 1);
insert into range_range values('201902', '2', '1', 1);
insert into range_range values('201902', '1', '1', 1);
insert into range_range values('201903', '2', '1', 1);
insert into range_range values('201903', '1', '1', 1);
insert into range_range values('201903', '2', '1', 1);
select * from range_range;
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201902     | 1         | 1       |         1
 201902     | 1         | 1       |         1
 201902     | 2         | 1       |         1
 201903     | 1         | 1       |         1
 201903     | 2         | 1       |         1
 201903     | 2         | 1       |         1
(6 rows)

drop table range_range;

  • Example 2: Truncate a level-2 partitioned table.

    CREATE TABLE list_list
(
    month_code VARCHAR2 ( 30 ) NOT NULL ,
    dept_code  VARCHAR2 ( 30 ) NOT NULL ,
    user_no    VARCHAR2 ( 30 ) NOT NULL ,
    sales_amt  int
)
PARTITION BY LIST (month_code) SUBPARTITION BY LIST (dept_code)
(
  PARTITION p_201901 VALUES ( '201902' )
  (
    SUBPARTITION p_201901_a VALUES ( '1' ),
    SUBPARTITION p_201901_b VALUES ( default )
  ),
  PARTITION p_201902 VALUES ( '201903' )
  (
    SUBPARTITION p_201902_a VALUES ( '1' ),
    SUBPARTITION p_201902_b VALUES ( '2' )
  )
);
insert into list_list values('201902', '1', '1', 1);
insert into list_list values('201902', '2', '1', 1);
insert into list_list values('201902', '1', '1', 1);
insert into list_list values('201903', '2', '1', 1);
insert into list_list values('201903', '1', '1', 1);
insert into list_list values('201903', '2', '1', 1);
select * from list_list;
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201903     | 2         | 1       |         1
 201903     | 2         | 1       |         1
 201903     | 1         | 1       |         1
 201902     | 2         | 1       |         1
 201902     | 1         | 1       |         1
 201902     | 1         | 1       |         1
(6 rows)

select * from list_list partition (p_201901);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201902     | 2         | 1       |         1
 201902     | 1         | 1       |         1
 201902     | 1         | 1       |         1
(3 rows)

alter table list_list truncate partition p_201901;
select * from list_list partition (p_201901);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
(0 rows)

select * from list_list partition (p_201902);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201903     | 2         | 1       |         1
 201903     | 2         | 1       |         1
 201903     | 1         | 1       |         1
(3 rows)

alter table list_list truncate partition p_201902;
select * from list_list partition (p_201902);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
(0 rows)

select * from list_list;
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
(0 rows)

insert into list_list values('201902', '1', '1', 1);
insert into list_list values('201902', '2', '1', 1);
insert into list_list values('201902', '1', '1', 1);
insert into list_list values('201903', '2', '1', 1);
insert into list_list values('201903', '1', '1', 1);
insert into list_list values('201903', '2', '1', 1);
select * from list_list subpartition (p_201901_a);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201902     | 1         | 1       |         1
 201902     | 1         | 1       |         1
(2 rows)

alter table list_list truncate subpartition p_201901_a;
select * from list_list subpartition (p_201901_a);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
(0 rows)

select * from list_list subpartition (p_201901_b);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201902     | 2         | 1       |         1
(1 row)

alter table list_list truncate subpartition p_201901_b;
select * from list_list subpartition (p_201901_b);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
(0 rows)

select * from list_list subpartition (p_201902_a);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201903     | 1         | 1       |         1
(1 row)

alter table list_list truncate subpartition p_201902_a;
select * from list_list subpartition (p_201902_a);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
(0 rows)

select * from list_list subpartition (p_201902_b);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201903     | 2         | 1       |         1
 201903     | 2         | 1       |         1
(2 rows)

alter table list_list truncate subpartition p_201902_b;
select * from list_list subpartition (p_201902_b);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
(0 rows)

select * from list_list;
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
(0 rows)

drop table list_list;

  • Example 3: Split a level-2 partitioned table.

    CREATE TABLE list_list
(
    month_code VARCHAR2 ( 30 ) NOT NULL ,
    dept_code  VARCHAR2 ( 30 ) NOT NULL ,
    user_no    VARCHAR2 ( 30 ) NOT NULL ,
    sales_amt  int
)
PARTITION BY LIST (month_code) SUBPARTITION BY LIST (dept_code)
(
  PARTITION p_201901 VALUES ( '201902' )
  (
    SUBPARTITION p_201901_a VALUES ( '1' ),
    SUBPARTITION p_201901_b VALUES ( default )
  ),
  PARTITION p_201902 VALUES ( '201903' )
  (
    SUBPARTITION p_201902_a VALUES ( '1' ),
    SUBPARTITION p_201902_b VALUES ( default )
  )
);
insert into list_list values('201902', '1', '1', 1);
insert into list_list values('201902', '2', '1', 1);
insert into list_list values('201902', '1', '1', 1);
insert into list_list values('201903', '2', '1', 1);
insert into list_list values('201903', '1', '1', 1);
insert into list_list values('201903', '2', '1', 1);
select * from list_list;
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201903     | 2         | 1       |         1
 201903     | 2         | 1       |         1
 201903     | 1         | 1       |         1
 201902     | 2         | 1       |         1
 201902     | 1         | 1       |         1
 201902     | 1         | 1       |         1
(6 rows)

select * from list_list subpartition (p_201901_a);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201902     | 1         | 1       |         1
 201902     | 1         | 1       |         1
(2 rows)

select * from list_list subpartition (p_201901_b);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201902     | 2         | 1       |         1
(1 row)

alter table list_list split subpartition p_201901_b values (2) into
(
 subpartition p_201901_b,
 subpartition p_201901_c
);
select * from list_list subpartition (p_201901_a);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201902     | 1         | 1       |         1
 201902     | 1         | 1       |         1
(2 rows)

select * from list_list subpartition (p_201901_b);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201902     | 2         | 1       |         1
(1 row)

select * from list_list subpartition (p_201901_c);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
(0 rows)

select * from list_list partition (p_201901);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201902     | 2         | 1       |         1
 201902     | 1         | 1       |         1
 201902     | 1         | 1       |         1
(3 rows)

select * from list_list subpartition (p_201902_a);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201903     | 1         | 1       |         1
(1 row)

select * from list_list subpartition (p_201902_b);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201903     | 2         | 1       |         1
 201903     | 2         | 1       |         1
(2 rows)

alter table list_list split subpartition p_201902_b values (3) into
(
 subpartition p_201902_b,
 subpartition p_201902_c
);
select * from list_list subpartition (p_201902_a);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201903     | 1         | 1       |         1
(1 row)

select * from list_list subpartition (p_201902_b);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
(0 rows)

select * from list_list subpartition (p_201902_c);
 month_code | dept_code | user_no | sales_amt
------------+-----------+---------+-----------
 201903     | 2         | 1       |         1
 201903     | 2         | 1       |         1
(2 rows)

drop table list_list;
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