---
{
    "title": "CREATE-VIEW",
    "language": "zh-CN"
}
---

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## CREATE-VIEW

### Name

CREATE VIEW

### Description

该语句用于创建一个逻辑视图
语法：

```sql
CREATE VIEW [IF NOT EXISTS]
 [db_name.]view_name
 (column1[ COMMENT "col comment"][, column2, ...])
AS query_stmt
```


说明：

- 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。
- query_stmt 为任意支持的 SQL

### Example

1. 在 example_db 上创建视图 example_view

    ```sql
    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

    ```sql
    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;
    ```

### Keywords

    CREATE, VIEW

### Best Practice