How to create a View Table with SQL statement

This article introduces the relevant knowledge of "how to use SQL sentences to create a view table". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

Visual tables (Views) can be treated as virtual tables. Unlike a table, there is actual data stored in the table, while the visual table is a structure based on the table, which does not actually store the data. The syntax for creating a view table is as follows:

CREATE VIEW "VIEW_NAME" AS "SQL statement"

The "SQL statement" can be any SQL that we have mentioned in this textbook. Let's look at an example. Suppose we have the following table:

TABLE Customer

(First_Name char (50)

Last_Name char (50)

Address char (50)

City char (50)

Country char (25)

Birth_Date date)

To create a visual table on this table that includes the three fields First_Name,Last_Name and Country, we enter:

CREATE VIEW V_Customer

AS SELECT First_Name, Last_Name, Country

FROM Customer

Now, we have a visual table called V_Customer:

View V_Customer

(First_Name char (50)

Last_Name char (50)

Country char (25))

We can also use visual tables to connect two tables. In this case, the user can find out the information she wants directly from a visual table without having to do a join action from two different tables. Suppose you have the following two tables:

Store_Information form

Store_name sales date

Los Angeles $1500 jan-05-1999

San Francisco $300 jan-08-1999

Boston $700 jan-08-1999

Geography form

Region_name store_name

East Boston

East New York

West Los Angeles

West San Diego

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

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 visual table called V_REGION_SALES. This view table contains sales from different regions. If we want to get data from this view table, we enter:

SELECT * FROM V_REGION_SALES

Results:

REGION SALES

East $700

West $2050

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