MySQL 8.4 Release Notes
27.5.1 视图语法
The CREATE VIEW
statement creates a new view (see Section 15.1.23, “CREATE VIEW Statement”). To alter the definition of a view or drop a view, use ALTER VIEW
(see Section 15.1.11, “ALTER VIEW Statement”), or DROP VIEW
(see Section 15.1.35, “DROP VIEW Statement”).
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 |
+------+-------+-------+