CREATE VIEW syntax in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a view named 'active_users' that selects all columns from the 'users' table.

SQL

CREATE VIEW active_users AS SELECT * FROM [1];

Drag options to blanks, or click blank then click option'

Ausers

Bproducts

Corders

Dcustomers

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a table unrelated to users like 'orders' or 'products'.

Forgetting to specify the table name after FROM.

The view 'active_users' should select data from the 'users' table, so the correct table name is 'users'.

2fill in blank

medium

Complete the code to create a view named 'high_salary_employees' that selects employees with salary greater than 50000.

SQL

CREATE VIEW high_salary_employees AS SELECT * FROM employees WHERE salary [1] 50000;

Drag options to blanks, or click blank then click option'

A<=

B<

C=

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using < or <= which select lower salaries.

Using = which selects only salaries exactly 50000.

The view should include employees with salary greater than 50000, so the correct operator is >.

3fill in blank

hard

Fix the error in the code to create a view named 'customer_emails' that selects only the email column from customers.

SQL

CREATE VIEW customer_emails AS SELECT [1] FROM customers;

Drag options to blanks, or click blank then click option'

Aemail

B*

Cemails

Dcustomer_email

Attempts:

3 left

💡 Hint

Common Mistakes

Using '*' which selects all columns instead of just email.

Using incorrect column names like 'emails' or 'customer_email'.

The column name is 'email', so selecting 'email' returns only that column. '*' selects all columns, which is not the goal.

4fill in blank

hard

Fill both blanks to create a view named 'recent_orders' that selects order_id and order_date from orders placed after 2023-01-01.

SQL

CREATE VIEW recent_orders AS SELECT [1], [2] FROM orders WHERE order_date > '2023-01-01';

Drag options to blanks, or click blank then click option'

Aorder_id

Border_date

Ccustomer_id

Dtotal_amount

Attempts:

3 left

💡 Hint

Common Mistakes

Selecting unrelated columns like 'customer_id' or 'total_amount'.

Forgetting to select both required columns.

The view should include 'order_id' and 'order_date' columns, so these are the correct selections.

5fill in blank

hard

Fill all three blanks to create a view named 'top_products' that selects product_name and price from products where price is greater than 100.

SQL

CREATE VIEW top_products AS SELECT [1], [2] FROM products WHERE [3] > 100;

Drag options to blanks, or click blank then click option'

Aproduct_name

Bprice

Dproduct_id

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'product_id' instead of 'product_name' or 'price'.

Filtering on a wrong column instead of 'price'.

The view selects 'product_name' and 'price' columns, and filters where 'price' is greater than 100.

Practice

1. What is the main purpose of the CREATE VIEW statement in SQL?

easy

A. To save a SELECT query as a virtual table

B. To permanently store data in the database

C. To delete rows from a table

D. To update existing records in a table

Solution

1. Step 1: Understand what a view is

   A view is a virtual table created by saving a SELECT query.

2. Step 2: Identify the purpose of CREATE VIEW

   CREATE VIEW stores the SELECT query so you can use it like a table without storing data.

3. Final Answer:

   To save a SELECT query as a virtual table -> Option A

4. Quick Check:

   CREATE VIEW = virtual table [OK]

Hint: Views save SELECT queries as virtual tables [OK]

Common Mistakes:

• Thinking views store data physically
• Confusing CREATE VIEW with INSERT or UPDATE
• Assuming views delete or modify data

2. Which of the following is the correct syntax to create a view named EmployeeView that selects all columns from the Employees table?

easy

A. CREATE EmployeeView VIEW AS SELECT * FROM Employees;

B. CREATE VIEW EmployeeView AS SELECT * FROM Employees;

C. VIEW CREATE EmployeeView AS SELECT * FROM Employees;

D. CREATE VIEW Employees AS SELECT * FROM EmployeeView;

Solution

1. Step 1: Recall the correct CREATE VIEW syntax

   The syntax is: CREATE VIEW view_name AS SELECT ...

2. Step 2: Match the syntax with options

   CREATE VIEW EmployeeView AS SELECT * FROM Employees; matches the correct syntax exactly.

3. Final Answer:

   CREATE VIEW EmployeeView AS SELECT * FROM Employees; -> Option B

4. Quick Check:

   CREATE VIEW view_name AS SELECT ... [OK]

Hint: CREATE VIEW view_name AS SELECT ... [OK]

Common Mistakes:

• Swapping keywords CREATE and VIEW
• Mixing table and view names incorrectly
• Using wrong keyword order

3. Given the view creation:
CREATE VIEW ActiveUsers AS SELECT id, name FROM Users WHERE active = 1;
What will the query SELECT * FROM ActiveUsers; return?

medium

A. Only users with active = 1

B. Only user IDs without names

C. An error because views cannot filter data

D. All users including inactive ones

Solution

1. Step 1: Understand the view definition

   The view selects id and name from Users where active = 1, so only active users are included.

2. Step 2: Analyze the SELECT from the view

   Selecting * from ActiveUsers returns all columns defined in the view, filtered by active = 1.

3. Final Answer:

   Only users with active = 1 -> Option A

4. Quick Check:

   View filters rows = active users only [OK]

Hint: View returns filtered rows as defined in SELECT [OK]

Common Mistakes:

• Assuming view returns all table rows
• Thinking views cannot filter data
• Expecting columns not in view to appear

4. Identify the error in this view creation statement:
CREATE VIEW SalesView SELECT * FROM Sales;

medium

A. SELECT * is not allowed in views

B. View name cannot be SalesView

C. Missing AS keyword before SELECT

D. CREATE VIEW must include WHERE clause

Solution

1. Step 1: Check the syntax of CREATE VIEW

   The correct syntax requires AS before the SELECT statement.

2. Step 2: Identify the missing keyword

   The statement misses AS, causing a syntax error.

3. Final Answer:

   Missing AS keyword before SELECT -> Option C

4. Quick Check:

   CREATE VIEW ... AS SELECT ... [OK]

Hint: Always include AS before SELECT in CREATE VIEW [OK]

Common Mistakes:

• Omitting AS keyword
• Misplacing SELECT clause
• Assuming WHERE clause is mandatory

5. You want to create a view TopProducts that shows product names and total sales only for products with sales over 1000. Which SQL statement correctly creates this view?

hard

A. CREATE VIEW TopProducts AS SELECT product_name, sales FROM Products WHERE sales > 1000;

B. CREATE VIEW TopProducts AS SELECT product_name, SUM(sales) FROM Products GROUP BY product_name WHERE SUM(sales) > 1000;

C. CREATE VIEW TopProducts AS SELECT product_name, SUM(sales) FROM Products WHERE SUM(sales) > 1000 GROUP BY product_name;

D. CREATE VIEW TopProducts AS SELECT product_name, SUM(sales) FROM Products GROUP BY product_name HAVING SUM(sales) > 1000;

Solution

1. Step 1: Understand the requirement

   We need product names and total sales, only for products with total sales over 1000.

2. Step 2: Use GROUP BY and HAVING correctly

   SUM(sales) requires GROUP BY product_name, and filtering on aggregated values uses HAVING.

3. Step 3: Check each option

   CREATE VIEW TopProducts AS SELECT product_name, SUM(sales) FROM Products GROUP BY product_name HAVING SUM(sales) > 1000; uses GROUP BY and HAVING correctly; others misuse WHERE or clause order.

4. Final Answer:

   CREATE VIEW TopProducts AS SELECT product_name, SUM(sales) FROM Products GROUP BY product_name HAVING SUM(sales) > 1000; -> Option D

5. Quick Check:

   Use HAVING for aggregated filters in views [OK]

Hint: Use HAVING for conditions on aggregates in views [OK]

Common Mistakes:

• Using WHERE with aggregate functions
• Placing WHERE after GROUP BY
• Omitting GROUP BY when using SUM