The CREATE VIEW statement creates a new view, which is a stored query represented as a virtual table.
Required Privileges
The user must have the CREATE privilege on the parent database and the SELECT privilege on any table(s) referenced by the view.
Synopsis
Parameters
| Parameter | Description |
|---|---|
view_name |
The name of the view to create, which must be unique within its database and follow these identifier rules. When the parent database is not set as the default, the name must be formatted as database.name. |
name_list |
An optional, comma-separated list of column names for the view. If specified, these names will be used in the response instead of the columns specified in AS select_stmt. |
AS select_stmt |
The selection query to execute when the view is requested. Note that it is not currently possible to use * to select all columns from a referenced table or view; instead, you must specify specific columns. |
Example
Let's say you're using our sample startrek database, which contains two tables, episodes and quotes. There's a foreign key constraint between the episodes.id column and the quotes.episode column. To count the number of famous quotes per season, you could run the following join:
> SELECT startrek.episodes.season, count(*)
FROM startrek.quotes
JOIN startrek.episodes
ON startrek.quotes.episode = startrek.episodes.id
GROUP BY startrek.episodes.season;
+--------+----------+
| season | count(*) |
+--------+----------+
| 2 | 76 |
| 3 | 46 |
| 1 | 78 |
+--------+----------+
(3 rows)
Alternatively, to make it much easier to run this complex query, you could create a view:
> CREATE VIEW startrek.quotes_per_season (season, quotes)
AS SELECT startrek.episodes.season, count(*)
FROM startrek.quotes
JOIN startrek.episodes
ON startrek.quotes.episode = startrek.episodes.id
GROUP BY startrek.episodes.season;
CREATE VIEW
The view is then represented as a virtual table alongside other tables in the database:
> SHOW TABLES FROM startrek;
+-------------------+
| Table |
+-------------------+
| episodes |
| quotes |
| quotes_per_season |
+-------------------+
(4 rows)
Executing the query is as easy as SELECTing from the view, as you would from a standard table:
> SELECT * FROM startrek.quotes_per_season;
+--------+--------+
| season | quotes |
+--------+--------+
| 2 | 76 |
| 3 | 46 |
| 1 | 78 |
+--------+--------+
(3 rows)
Known Limitations
It is not yet possible to use a common table expression inside the selection query used to define a view.
See Also
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