CREATE VIEW 7 SQL - Language Statements CREATE VIEW define a new view CREATE VIEW CREATE [ OR REPLACE ] [ TEMP | TEMPORARY ] VIEW name [ ( column_name [, ...] ) ] AS query CREATE VIEW defines a view of a query. The view is not physically materialized. Instead, the query is run every time the view is referenced in a query. CREATE OR REPLACE VIEW is similar, but if a view of the same name already exists, it is replaced. The new query must generate the same columns that were generated by the existing view query (that is, the same column names in the same order and with the same data types), but it may add additional columns to the end of the list. The calculations giving rise to the output columns may be completely different. If a schema name is given (for example, CREATE VIEW myschema.myview ...) then the view is created in the specified schema. Otherwise it is created in the current schema. Temporary views exist in a special schema, so a schema name cannot be given when creating a temporary view. The name of the view must be distinct from the name of any other view, table, sequence, or index in the same schema. TEMPORARY or TEMP If specified, the view is created as a temporary view. Temporary views are automatically dropped at the end of the current session. Existing permanent relations with the same name are not visible to the current session while the temporary view exists, unless they are referenced with schema-qualified names. If any of the tables referenced by the view are temporary, the view is created as a temporary view (whether TEMPORARY is specified or not). name The name (optionally schema-qualified) of a view to be created. column_name An optional list of names to be used for columns of the view. If not given, the column names are deduced from the query. query A or command which will provide the columns and rows of the view. Some views are updatable, which means that the commands INSERT, UPDATE, and DELETE can be used on the view as if it were a regular table. A view is updatable if it does not contain: more than one underlying table (joins) or no underlying table at all underlying tables/views that are themselves not updatable, including table value constructors and table functions subqueries in the FROM list items in the select list that are not direct references to a column of the underlying table, such as literals or any nontrivial value expression references to system columns in the select list more than one reference to the same column in the select list aggregate function calls window function calls WITH or WITH RECURSIVE clauses DISTINCT, GROUP BY, or HAVING clauses UNION, INTERSECT, or EXCEPT clauses LIMIT or OFFSET clauses (or other equivalent spellings thereof) The updatable views implementation is based on the rule system. Because of this, you can also make more complex views updatable or insertable by creating your own rules that rewrite the INSERT, UPDATE, and DELETE actions on the view into appropriate actions on other tables. You can also replace the automatically generated rules by your own rules. For more information on the rule system, refer to . Use the statement to drop views. Be careful that the names and types of the view's columns will be assigned the way you want. For example: CREATE VIEW vista AS SELECT 'Hello World'; is bad form in two ways: the column name defaults to ?column?, and the column data type defaults to unknown. If you want a string literal in a view's result, use something like: CREATE VIEW vista AS SELECT text 'Hello World' AS hello; Access to tables referenced in the view is determined by permissions of the view owner. However, functions called in the view are treated the same as if they had been called directly from the query using the view. Therefore the user of a view must have permissions to call all functions used by the view. Create a view consisting of all comedy films: CREATE VIEW comedies AS SELECT * FROM films WHERE kind = 'Comedy'; The SQL standard specifies some additional capabilities for the CREATE VIEW statement: CREATE VIEW name [ ( column_name [, ...] ) ] AS query [ WITH [ CASCADED | LOCAL ] CHECK OPTION ] The optional clauses for the full SQL command are: CHECK OPTION This option has to do with updatable views. All INSERT and UPDATE commands on the view will be checked to ensure data satisfy the view-defining condition (that is, the new data would be visible through the view). If they do not, the update will be rejected. LOCAL Check for integrity on this view. CASCADED Check for integrity on this view and on any dependent view. CASCADED is assumed if neither CASCADED nor LOCAL is specified. CREATE OR REPLACE VIEW is a PostgreSQL language extension. So is the concept of a temporary view.