How To Create View In Db2

Summary: in this tutorial, you will learn how to use the Db2 CREATE VIEW statement to create new views in the database.

Introduction to Db2 `CREATE VIEW` statement

To create a new view in the database, you use the CREATE VIEW statement. The basic syntax for creating a view is the following:

CREATE VIEW view_name (view_column_list) AS select_statement;

Code language: SQL (Structured Query Language) ( sql )

In this syntax:

First, specify the name of the view which you want to create after the CREATE VIEW keywords. The column names of the view will automatically derive from the select_statement. However, you can tailor the column names for the view by explicitly declare them in parentheses following the view name.
Second, specify a SELECT statement that retrieves data from columns of one or more tables.

Db2 `CREATE VIEW` statement examples

Let's take some examples of creating new views. We'll use the books, book_authors, and publishers tables from the sample database for the demonstration.

1) Creating a view based on partial data of a table

See this books table:

The following statement uses the CREATE VIEW statement to create a new view based on the books table that returns all books published since January 2018.

                                          CREATE                VIEW                new_books                AS                SELECT                title,      rating,      isbn,      published_date                FROM                books                WHERE                published_date >                '2018-01-01';                          
                          Code language:              SQL (Structured Query Language)              (              sql              )

Here is the data returned via the view:

                                          SELECT                *                FROM                new_books                ORDER                BY                title;                          
                          Code language:              SQL (Structured Query Language)              (              sql              )

DB2 create view based on partial data of a table example

2) Creating a view based on multiple tables example

This example uses the CREATE TABLE statement to create a view based on the books and publishers tables:

                                          CREATE                VIEW                book_details                AS                SELECT                b.title,         b.rating,         b.isbn,         p.name publisher,         b.published_date                FROM                books b                INNER                JOIN                publishers p                ON                p.publisher_id = b.publisher_id;                          
                          Code language:              SQL (Structured Query Language)              (              sql              )

The following statement returns data from the view:

                                          SELECT                *                FROM                book_details                ORDER                BY                title;                          
                          Code language:              SQL (Structured Query Language)              (              sql              )

DB2 create view based on data from multiple tables

3) Creating a view based on summary data from tables

This statement creates a new view that returns the book title and the number of authors of each book:

                                          CREATE                VIEW                book_author_stats (         book_title,          author_count )                AS                SELECT                title,                COUNT(A.author_id)                FROM                books b                INNER                JOIN                book_authors a                ON                a.book_id = b.book_id                GROUP                BY                title;                          
                          Code language:              SQL (Structured Query Language)              (              sql              )

The following query returns the data from the book_author_stats view:

                                          SELECT                book_title,      author_count                FROM                book_author_stats                ORDER                BY                book_title;                          
                          Code language:              SQL (Structured Query Language)              (              sql              )

DB2 create view based on summarized data of other tables

In this tutorial, you have learned how to use the Db2 CREATE VIEW statement to create new views in the database.

Was this tutorial helpful ?