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What is the purpose of SQL roles?
What is the purpose of transaction logs in PostgreSQL?
sales, which contains information about sales transactions. The sales table has columns for the date of the transaction, the name of the salesperson, the product sold, and the amount of the sale. You want to create a grouped view that shows the total sales amount for each salesperson and product combination.Example of the sales table:
| sale_date | salesperson | product | sale_amount |
|---|---|---|---|
| 2022-03-01 | John Smith | Product A | 100.00 |
| 2022-03-01 | Jane Doe | Product B | 75.00 |
| 2022-03-02 | John Smith | Product C | 50.00 |
| 2022-03-03 | Bob Johnson | Product A | 25.00 |
| 2022-03-03 | Jane Doe | Product B | 150.00 |
Which of the following CREATE VIEW statements would accomplish this?
customers and orders, with the following data:customers table:
| customer_id | customer_name | address | city |
|---|---|---|---|
| 1 | John Smith | 123 Main St. | Anytown |
| 2 | Jane Doe | 456 Oak St. | Other town |
| 3 | Bob Johnson | 789 Maple Ave. | Another town |
orders table:
| order_id | customer_id | order_date | total_amount |
|---|---|---|---|
| 1 | 1 | 2022-03-01 | 150.00 |
| 2 | 2 | 2022-03-02 | 75.00 |
| 3 | 1 | 2022-03-03 | 25.00 |
| 4 | 3 | 2022-03-04 | 50.00 |
Which of the following CREATE VIEW statements would create a vertical view that displays the customer name, order ID, and total amount for all orders?
orders, order_details and customers. The orders table contains basic information about each order, including the order ID and customer ID, customers table contains information about customer, while the order_details table contains the details of each order, including the product ID, quantity, and price. You want to create a view that shows the order ID, customer name, product name, quantity, and price for all orders.
Example of the orders table:
| order_id | customer_id | order_date |
|---|---|---|
| 1 | 1 | 2022-03-01 |
| 2 | 2 | 2022-03-02 |
| 3 | 1 | 2022-03-03 |
| 4 | 3 | 2022-03-04 |
Example of the order_details table:
| order_id | product_id | quantity | price |
|---|---|---|---|
| 1 | 1 | 3 | 10.00 |
| 2 | 2 | 5 | 15.00 |
| 1 | 3 | 2 | 20.00 |
| 4 | 1 | 1 | 8.50 |
Example of the customers table:
| customer_id | customer_name | city |
|---|---|---|
| 1 | Laurence Lebihan | London |
| 2 | Diego Roel | Madrid |
Which of the following CREATE VIEW statements would accomplish this?
orders and products. You want to create a view that shows the order ID, product name, and quantity for all orders that include a particular product. Which of the following CREATE VIEW statements would accomplish this?Table Example:orders table:| order_id | product_id | quantity |
|----------|------------|----------|
| 1 | 1 | 3 |
| 2 | 2 | 5 |
| 3 | 1 | 2 |
| 4 | 3 | 1 |
products table:
| id | product_name |
|----|--------------|
| 1 | Widget A |
| 2 | Widget B |
| 3 | Widget C |
What is the difference between a regular view and a materialized view in PostgreSQL?
What is the benefit of using materialized (indexed) views?