Linux SQL statement Concise tutorial---CREATE VIEW

A view view can be used as a virtual table. It differs from the table in that there are actual data stored in the table, and that the view table is an architecture built on top of the table, which itself does not actually store the data.

The syntax for creating a view table is as follows:

CREATE VIEW "view_name" as "SQL statement";

"SQL statement" can be any of the SQL that we have mentioned in this textbook.

Take a look at an example. Suppose we have the following table:

Customer Table

Field name	Type of information
First_Name	CHAR (50)
Last_Name	CHAR (50)
Address	CHAR (50)
City	CHAR (50)
Country	CHAR (25)
Birth_date	Datetime

To create a view of the three fields, including First_Name, last_name, and country, on this form, we enter

CREATE VIEW V_customer
As SELECT first_name, last_name, country
from Customer;

Now, we have a visual watch called V_customer :

v_customer View table

Field name	Type of information
First_Name	CHAR (50)
Last_Name	CHAR (50)
Country	CHAR (25)

We can also connect two tables using a view table. In this case, the user can find the information she wants directly from a view table, without having to make a connection action from two different tables. Suppose you have the following two tables:

store_information Form

Store_name	Sales	Txn_date
Los Angeles	1500	05-jan-1999
San Diego	250	07-jan-1999
Los Angeles	300	08-jan-1999
Boston	700	08-jan-1999

Geography Form

Region_name	Store_name
East	Boston
East	New York
West	Los Angeles
West	San Diego

We can use the following instructions to build a view table that includes sales for each region (sales):

CREATE VIEW V_region_sales
As SELECT A1. Region_name region, SUM (A2. Sales) Sales
From Geography A1, Store_information A2
WHERE A1. Store_name = A2. Store_name
GROUP by A1. Region_name;

This gives us a view of the V_region_sales called a watch. This view list includes sales in different regions. If we're going to get the information from this view, we'll break in,

SELECT * from V_region_sales;

Results:

Region	SALES
East	700
West	2050

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Linux SQL statement Concise tutorial---CREATE VIEW