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如何在MySQL中创建一个空的VIEW？

2024-04-25 20:25:04 468

要在MySQL中创建一个空视图，以下是语法-

create or replace view yourViewName as
select yourValue AS yourColumnName,
yourValue AS yourColumnName2,
.
.
N
from dual
where false;

让我们实现上述语法，以便在MySQL中创建一个空视图-

mysql> create or replace view empty_view as
   select "John Smith" AS ClientName,
   "US" AS ClientCountryName,
   false AS isMarried
   from dual
   where false;

让我们检查视图的描述-

mysql> desc empty_view;

这将产生以下输出-

+-------------------+-------------+------+-----+---------+-------+
| Field             | Type        | Null | Key | Default | Extra |
+-------------------+-------------+------+-----+---------+-------+
| ClientName        | varchar(10) | NO   |     |         |       |
| ClientCountryName | varchar(2)  | NO   |     |         |       |
| isMarried         | int(1)      | NO   |     | 0       |       |
+-------------------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

让我们检查视图是否为空-

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

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如何在MySQL中创建一个空的VIEW？

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