Spec-Zone .ru
спецификации, руководства, описания, API
|
The CREATE VIEW
statement creates a new view (see Section
13.1.20, "CREATE VIEW
Syntax"). To alter the definition of a view or drop a
view, use ALTER VIEW
(see Section 13.1.9, "ALTER VIEW
Syntax"), or DROP VIEW
(see Section 13.1.31, "DROP VIEW
Syntax").
A view can be created from many kinds of SELECT
statements. It can refer to base tables or other views. It can use joins,
UNION
, and subqueries. The SELECT
need not even refer to any tables. The following example defines a
view that selects two columns from another table, as well as an expression calculated from those columns:
mysql>CREATE TABLE t (qty INT, price INT);
mysql>INSERT INTO t VALUES(3, 50), (5, 60);
mysql>CREATE VIEW v AS SELECT qty, price, qty*price AS value FROM t;
mysql>SELECT * FROM v;
+------+-------+-------+| qty | price | value |+------+-------+-------+| 3 | 50 | 150 || 5 | 60 | 300 |+------+-------+-------+mysql>SELECT * FROM v WHERE qty = 5;
+------+-------+-------+| qty | price | value |+------+-------+-------+| 5 | 60 | 300 |+------+-------+-------+