CREATE VIEW

description

该语句用于创建一个逻辑视图
语法：
    CREATE VIEW [IF NOT EXISTS]
    [db_name.]view_name
    (column1[ COMMENT "col comment"][, column2, ...])
    AS query_stmt
说明：
    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。
    2. query_stmt 为任意支持的 SQL

example

1. 在 example_db 上创建视图 example_view
    CREATE VIEW example_db.example_view (k1, k2, k3, v1)
    AS
    SELECT c1 as k1, k2, k3, SUM(v1) FROM example_table
    WHERE k1 = 20160112 GROUP BY k1,k2,k3;
2. 创建一个包含 comment 的 view
    CREATE VIEW example_db.example_view
    (
        k1 COMMENT "first key",
        k2 COMMENT "second key",
        k3 COMMENT "third key",
        v1 COMMENT "first value"
    )
    COMMENT "my first view"
    AS
    SELECT c1 as k1, k2, k3, SUM(v1) FROM example_table
    WHERE k1 = 20160112 GROUP BY k1,k2,k3;

keyword

CREATE,VIEW