如何在mySQL中创建一个空的VIEW

Question

我试图用我定义的列在mySQL中创建一个空的VIEW.

即我想要一个列的视图:年龄,身份,性别,但有0行.

提前致谢.

Answer 1

为什么你想要这样做是超出我的:

CREATE VIEW foo AS SELECT NULL AS age, NULL AS id, NULL AS gender WHERE FALSE

Answer 2

这是给你的一个例子:

mysql> create or replace view v_test as 
    -> select 99 as age, 
    ->   2147483647 as id, 
    ->   'F' as gender 
    -> from dual 
    -> where false;
Query OK, 0 rows affected (0.04 sec)

mysql> desc v_test;
+--------+------------+------+-----+---------+-------+
| Field  | Type       | Null | Key | Default | Extra |
+--------+------------+------+-----+---------+-------+
| age    | int(2)     | NO   |     | 0       |       |
| id     | bigint(10) | NO   |     | 0       |       |
| gender | varchar(1) | NO   |     |         |       |
+--------+------------+------+-----+---------+-------+
3 rows in set (0.01 sec)

mysql> select * from v_test;
Empty set (0.00 sec)