Presto 324 Documentation

9.11. CREATE VIEW

9.11. CREATE VIEW

Synopsis

CREATE [ OR REPLACE ] VIEW view_name
[ SECURITY { DEFINER | INVOKER } ]
AS query

Description

Create a new view of a SELECT query. The view is a logical table that can be referenced by future queries. Views do not contain any data. Instead, the query stored by the view is executed everytime the view is referenced by another query.

The optional OR REPLACE clause causes the view to be replaced if it already exists rather than raising an error.

Security

In the default DEFINER security mode, tables referenced in the view are accessed using the permissions of the view owner (the creator or definer of the view) rather than the user executing the query. This allows providing restricted access to the underlying tables, for which the user may not be allowed to access directly.

In the INVOKER security mode, tables referenced in the view are accessed using the permissions of the user executing the query (the invoker of the view). A view created in this mode is simply a stored query.

Regardless of the security mode, the current_user function will always return the user executing the query and thus may be used within views to filter out rows or otherwise restrict access.

Examples

Create a simple view test over the orders table:

CREATE VIEW test AS
SELECT orderkey, orderstatus, totalprice / 2 AS half
FROM orders

Create a view orders_by_date that summarizes orders:

CREATE VIEW orders_by_date AS
SELECT orderdate, sum(totalprice) AS price
FROM orders
GROUP BY orderdate

Create a view that replaces an existing view:

CREATE OR REPLACE VIEW test AS
SELECT orderkey, orderstatus, totalprice / 4 AS quarter
FROM orders