Accessing a PARTITION or SUBPARTITION v18

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For a partitioned table, you can access the partition or subpartition using PARTITION part_name or SUBPARTITION subpart_name. This example creates a partitioned table sales that's range partitioned by date and subpartitioned using list partitioning by the country column:

CREATE TABLE sales
(
  dept_no     number,
  part_no     varchar2,
  country     varchar2(20),
  date        date,
  amount      number
)
PARTITION BY RANGE(date)
  SUBPARTITION BY LIST(country)
(
  PARTITION q1_2020 
    VALUES LESS THAN('2020-Apr-01')
    (
      SUBPARTITION q1_europe VALUES ('FRANCE', 'ITALY'),
      SUBPARTITION q1_asia VALUES ('INDIA', 'PAKISTAN'),
      SUBPARTITION q1_americas VALUES ('US', 'CANADA')
    ), 
  PARTITION q2_2020 
    VALUES LESS THAN('2020-Jul-01')
    (
      SUBPARTITION q2_europe VALUES ('FRANCE', 'ITALY'),
      SUBPARTITION q2_asia VALUES ('INDIA', 'PAKISTAN'),
      SUBPARTITION q2_americas VALUES ('US', 'CANADA')
    )
);

The SELECT statement shows two partitions. Each partition has three subpartitions.

edb=# SELECT subpartition_name, high_value, partition_name FROM ALL_TAB_SUBPARTITIONS;

Output

 subpartition_name |     high_value      | partition_name 
-------------------+---------------------+----------------
 Q1_EUROPE         | 'FRANCE', 'ITALY'   | Q1_2020
 Q1_ASIA           | 'INDIA', 'PAKISTAN' | Q1_2020
 Q1_AMERICAS       | 'US', 'CANADA'      | Q1_2020
 Q2_EUROPE         | 'FRANCE', 'ITALY'   | Q2_2020
 Q2_ASIA           | 'INDIA', 'PAKISTAN' | Q2_2020
 Q2_AMERICAS       | 'US', 'CANADA'      | Q2_2020
(6 rows)

This INSERT statement inserts rows into the sales table using specific PARTITION part_name or SUBPARTITION subpart_name values:

INSERT INTO sales PARTITION (q1_2020) VALUES (10, 'q1_2020', 'FRANCE', '2020-Feb-01', '500000');
INSERT INTO sales PARTITION (q2_2020) VALUES (10, 'q2_2020', 'ITALY', '2020-Apr-01', '550000');
INSERT INTO sales SUBPARTITION (q1_europe) VALUES (10, 'q1_europe', 'FRANCE', '2020-Feb-01', '600000');
INSERT INTO sales SUBPARTITION (q2_asia) VALUES (10, 'q2_asia', 'INDIA', '2020-Apr-01', '650000');

edb=# SELECT tableoid::regclass, * FROM sales ORDER BY date;

Output

    tableoid     | dept_no |  part_no  | country |        date        | amount 
-----------------+---------+-----------+---------+--------------------+--------
 sales_q1_europe |      10 | q1_2020   | FRANCE  | 01-FEB-20 00:00:00 | 500000
 sales_q1_europe |      10 | q1_europe | FRANCE  | 01-FEB-20 00:00:00 | 600000
 sales_q2_europe |      10 | q2_2020   | ITALY   | 01-APR-20 00:00:00 | 550000
 sales_q2_asia   |      10 | q2_asia   | INDIA   | 01-APR-20 00:00:00 | 650000
(4 rows)

Use this query to fetch the values from a specific partition q1_2020 or subpartition q1_europe:

edb=# SELECT tableoid::regclass, * FROM sales PARTITION (q1_2020) ORDER BY date;
    tableoid     | dept_no |  part_no  | country |        date        | amount 
-----------------+---------+-----------+---------+--------------------+--------
 sales_q1_europe |      10 | q1_2020   | FRANCE  | 01-FEB-20 00:00:00 | 500000
 sales_q1_europe |      10 | q1_europe | FRANCE  | 01-FEB-20 00:00:00 | 600000
(2 rows)

edb=# SELECT tableoid::regclass, country FROM sales SUBPARTITION (q1_europe) ORDER BY date;
    tableoid     | country 
-----------------+---------
 sales_q1_europe | FRANCE
 sales_q1_europe | FRANCE
(2 rows)

This SELECT statement selects rows from a specific partition or subpartition of a partitioned table by specifying the keyword PARTITION or SUBPARTITION:

edb=# SELECT tableoid::regclass, * FROM sales PARTITION (q2_2020) ORDER BY country;

Output

    tableoid     | dept_no | part_no | country |        date        | amount 
-----------------+---------+---------+---------+--------------------+--------
 sales_q2_asia   |      10 | q2_asia | INDIA   | 01-APR-20 00:00:00 | 650000
 sales_q2_europe |      10 | q2_2020 | ITALY   | 01-APR-20 00:00:00 | 550000
(2 rows)

edb=# SELECT tableoid::regclass, date FROM sales SUBPARTITION (q2_asia) ORDER BY country;

Output

   tableoid    |        date        
---------------+--------------------
 sales_q2_asia | 01-APR-20 00:00:00
(1 row)

This UPDATE statement updates values in a partition or subpartition of the sales table:

edb=# UPDATE sales PARTITION (q1_2020) SET amount = 10000 WHERE amount = 500000 RETURNING tableoid::regclass, *;

Output

    tableoid     | dept_no | part_no | country |        date        | amount 
-----------------+---------+---------+---------+--------------------+--------
 sales_q1_europe |      10 | q1_2020 | FRANCE  | 01-FEB-20 00:00:00 |  10000
(1 row)

UPDATE 1

edb=# UPDATE sales SUBPARTITION (q1_europe) SET amount = 5000 WHERE amount = 600000 RETURNING tableoid::regclass, *;

Output

    tableoid     | dept_no |  part_no  | country |        date        | amount 
-----------------+---------+-----------+---------+--------------------+--------
 sales_q1_europe |      10 | q1_europe | FRANCE  | 01-FEB-20 00:00:00 |   5000
(1 row)

UPDATE 1

This DELETE statement removes rows from the partition q2_2020 or subpartition q2_asia of the sales table:

edb=# DELETE FROM sales PARTITION (q2_2020) WHERE amount = 550000 RETURNING tableoid::regclass, *;

Output

    tableoid     | dept_no | part_no | country |        date        | amount 
-----------------+---------+---------+---------+--------------------+--------
 sales_q2_europe |      10 | q2_2020 | ITALY   | 01-APR-20 00:00:00 | 550000
(1 row)

DELETE 1

edb=# DELETE FROM sales SUBPARTITION (q2_asia) RETURNING tableoid::regclass, *;

Output

   tableoid    | dept_no | part_no | country |        date        | amount 
---------------+---------+---------+---------+--------------------+--------
 sales_q2_asia |      10 | q2_asia | INDIA   | 01-APR-20 00:00:00 | 650000
(1 row)

DELETE 1

Using alias for accessing PARTITION or SUBPARTITION

You can use aliases with SELECT, INSERT, UPDATE, or DELETE statements to access a partition or subpartition. This example creates a partitioned table sales that's range partitioned by date and subpartitioned using list partitioning by the country column:

CREATE TABLE sales
(
  dept_no     number,
  part_no     varchar2,
  country     varchar2(20),
  date        date,
  amount      number
)
PARTITION BY RANGE(date)
  SUBPARTITION BY LIST(country)
(
  PARTITION q1_2020 
    VALUES LESS THAN('2020-Apr-01')
    (
      SUBPARTITION q1_europe VALUES ('FRANCE', 'ITALY'),
      SUBPARTITION q1_asia VALUES ('INDIA', 'PAKISTAN'),
      SUBPARTITION q1_americas VALUES ('US', 'CANADA')
    ), 
  PARTITION q2_2020 
    VALUES LESS THAN('2020-Jul-01')
    (
      SUBPARTITION q2_europe VALUES ('FRANCE', 'ITALY'),
      SUBPARTITION q2_asia VALUES ('INDIA', 'PAKISTAN'),
      SUBPARTITION q2_americas VALUES ('US', 'CANADA')
    )
);

The SELECT statement shows two partitions. Each partition has three subpartitions.

edb=# SELECT subpartition_name, high_value, partition_name FROM ALL_TAB_SUBPARTITIONS;

Output

 subpartition_name |     high_value      | partition_name 
-------------------+---------------------+----------------
 Q1_EUROPE         | 'FRANCE', 'ITALY'   | Q1_2020
 Q1_ASIA           | 'INDIA', 'PAKISTAN' | Q1_2020
 Q1_AMERICAS       | 'US', 'CANADA'      | Q1_2020
 Q2_EUROPE         | 'FRANCE', 'ITALY'   | Q2_2020
 Q2_ASIA           | 'INDIA', 'PAKISTAN' | Q2_2020
 Q2_AMERICAS       | 'US', 'CANADA'      | Q2_2020
(6 rows)

This INSERT statement creates an alias of the sales table and inserts rows into partition q1_2020 and q2_2020 or subpartition q1_europe and q1_asia:

INSERT INTO sales PARTITION (q1_2020) AS q1_sales VALUES (10, 'q1_2020', 'FRANCE', '2020-Feb-01', '500000');
INSERT INTO sales PARTITION (q2_2020) q2_sales (q2_sales.dept_no, q2_sales.part_no, q2_sales.country, q2_sales.date, q2_sales.amount) VALUES (20, 'q2_2020', 'ITALY', '2020-Apr-01', '550000');
INSERT INTO sales SUBPARTITION (q1_europe) AS sales_q1_europe VALUES (10, 'q1_europe', 'FRANCE', '2020-Feb-01', '600000');
INSERT INTO sales SUBPARTITION (q1_asia) sales_q1_asia (sales_q1_asia.dept_no, sales_q1_asia.part_no, sales_q1_asia.country, sales_q1_asia.date, sales_q1_asia.amount) VALUES (20, 'q1_asia', 'INDIA', '2020-Mar-01', '650000');

This SELECT statement selects rows from a specific partition or subpartition of a sales table:

edb=# SELECT tableoid::regclass, * FROM sales PARTITION (q1_2020) AS q1_sales ORDER BY country;

Output

    tableoid     | dept_no |  part_no  | country |        date        | amount 
-----------------+---------+-----------+---------+--------------------+--------
 sales_q1_europe |      10 | q1_2020   | FRANCE  | 01-FEB-20 00:00:00 | 500000
 sales_q1_europe |      10 | q1_europe | FRANCE  | 01-FEB-20 00:00:00 | 600000
 sales_q1_asia   |      20 | q1_asia   | INDIA   | 01-MAR-20 00:00:00 | 650000
(3 rows)

edb=# SELECT tableoid::regclass, * FROM sales SUBPARTITION (q1_europe) sales_q1_europe ORDER BY country;

Output

    tableoid     | dept_no |  part_no  | country |        date        | amount 
-----------------+---------+-----------+---------+--------------------+--------
 sales_q1_europe |      10 | q1_2020   | FRANCE  | 01-FEB-20 00:00:00 | 500000
 sales_q1_europe |      10 | q1_europe | FRANCE  | 01-FEB-20 00:00:00 | 600000
(2 rows)

This UPDATE statement updates values in a partition or subpartition of the sales table:

edb=# UPDATE sales PARTITION (q1_2020) AS q1_sales SET q1_sales.amount = 10000 WHERE q1_sales.amount = 500000;
UPDATE 1

edb=# UPDATE sales SUBPARTITION (q1_europe) sales_q1_europe SET sales_q1_europe.amount = 5000 WHERE sales_q1_europe.amount = 600000;
UPDATE 1

This DELETE statement removes rows from the partition q1_2020 or subpartition q1_europe of the sales table:

edb=# DELETE FROM sales PARTITION (q1_2020) q1_sales WHERE q1_sales.amount = 10000;
DELETE 1

edb=# DELETE FROM sales SUBPARTITION (q1_europe) AS sales_q1_europe WHERE sales_q1_europe.amount = 5000;
DELETE 1

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Using alias for accessing PARTITION or SUBPARTITION

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Accessing a PARTITION or SUBPARTITION v18

Using alias for accessing PARTITION or SUBPARTITION

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