Help Center/ GaussDB/ Feature Guide(Distributed_8.x)/ Materialized View/ Complete-Refresh Materialized View/ Usage
Updated on 2024-06-07 GMT+08:00
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Usage

Syntax

  • Create a complete-refresh materialized view. 
    CREATE MATERIALIZED VIEW view_name AS query;
  • Refresh a complete-refresh materialized view. 
    REFRESH MATERIALIZED VIEW view_name;
  • Drop a materialized view. 
    DROP MATERIALIZED VIEW view_name;
  • Query a materialized view. 
    SELECT * FROM view_name;

Parameters

  • view_name

    Specifies the name of the materialized view to be created.

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

  • AS query

    Specifies a SELECT or VALUES command, or an EXECUTE command that runs a prepared SELECT or VALUES query.

Examples

-- Change the default type of a table.
gaussdb=#  set enable_default_ustore_table=off;

-- Prepare data.
CREATE TABLE t1(c1 int, c2 int);
INSERT INTO t1 VALUES(1, 1);
INSERT INTO t1 VALUES(2, 2);

-- Create a complete-refresh materialized view.
gaussdb=# CREATE MATERIALIZED VIEW mv AS select count(*) from t1;
CREATE MATERIALIZED VIEW

-- Query the materialized view result.
gaussdb=# SELECT * FROM mv;
 count 
-------
     2
(1 row)

-- Insert data into the base table in the materialized view again.
gaussdb=# INSERT INTO t1 VALUES(3, 3);

-- Completely refresh a complete-refresh materialized view.
gaussdb=# REFRESH MATERIALIZED VIEW mv;
REFRESH MATERIALIZED VIEW

-- Query the materialized view result.
gaussdb=# SELECT * FROM mv;
 count 
-------
     3
(1 row)

-- Drop the materialized view and table.
gaussdb=# DROP MATERIALIZED VIEW mv;
DROP MATERIALIZED VIEW
gaussdb=# DROP TABLE t1; 
DROP TABLE