CREATE VIEW

description

1. 该语句用于创建一个逻辑视图
2. 语法：
3. CREATE VIEW [IF NOT EXISTS]
4. [db_name.]view_name
5. (column1[ COMMENT "col comment"][, column2, ...])
6. AS query_stmt

8. 说明：
9. 1. 视图为逻辑视图，没有物理存储。所有在视图上的查询相当于在视图对应的子查询上进行。
10. 2. query_stmt 为任意支持的 SQL

example

1. 1. 在 example_db 上创建视图 example_view

3. CREATE VIEW example_db.example_view (k1, k2, k3, v1)
4. AS
5. SELECT c1 as k1, k2, k3, SUM(v1) FROM example_table
6. WHERE k1 = 20160112 GROUP BY k1,k2,k3;

8. 2. 创建一个包含 comment 的 view

10. CREATE VIEW example_db.example_view
11. (
12. k1 COMMENT "first key",
13. k2 COMMENT "second key",
14. k3 COMMENT "third key",
15. v1 COMMENT "first value"
16. )
17. COMMENT "my first view"
18. AS
19. SELECT c1 as k1, k2, k3, SUM(v1) FROM example_table
20. WHERE k1 = 20160112 GROUP BY k1,k2,k3;

keyword

1. CREATE,VIEW