> For the complete documentation index, see [llms.txt](https://gchandra.gitbook.io/data-warehousing/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gchandra.gitbook.io/data-warehousing/rdbms/sql-concepts/views.md).

# Views

* A view is a virtual table based on the result set of an SQL statement.
* A view is a data object which does not contain any data.
* Contents of the view are the result of a base table.
* They are operated just like a base table but don’t contain any data.
* The difference between a view and a table is that views are definitions built on top of other tables (or views).
* If data is changed in the underlying table, the view reflects the exact change.
* A view can be built on top of single or multiple tables.

### Simple Syntax

```
Create view <viewname>  as <select query>
```

### Example

```
use chandr34;

create view vw_album as select * from Chinook.Album where ArtistId > 8;

create view chandr34.vw_customer as select customer_id, customer_first_name 
from murach.customers;

select * from chandr34.vw_customer;

create View chandr34.vw_customer as 

select customer_id, concat_ws(' ',customer_first_name, customer_last_name) as customer_name 
from murach.customers;
```

### View Inside a View

```
create view chandr34.vw_customer1 as select * from vw_customer;
```

### Alter Views

#### Views can be used in SubQuery, Derived Tables.

```
Alter view <viewname> as <select query>

alter view vw_album as select * from Chinook.Album;

Alter View chandr34.vw_customer as 

select customer_id, concat_ws(',',customer_first_name, customer_last_name) as customer_name from murach.customers;

```

### Drop Views

```
Drop view <viewname>;
```

```
drop view vw_album;
```