SQL and Database Concepts Quiz

What does the SELECT clause do in SQL?

• It retrieves data from a database.

• It inserts data into a database.

• It updates data in a database.

• It deletes data from a database.

How do you filter records in a SQL query?

• Using the WHERE clause

• Using the SELECT clause

• Using the FROM clause

• Using the JOIN clause

What is the purpose of the ORDER BY clause in SQL?

• To filter records based on a condition

• To sort the result set in ascending or descending order

• To group records that have the same values

• To join two or more tables

How can you retrieve unique values from a column?

• Use the DISTINCT keyword

• Use the GROUP BY clause

• Use the UNIQUE function

• Use the SELECT ALL statement

How do you select all columns from a table named "Employees"?

• SELECT * FROM Employees;

• SELECT all FROM Employees;

• SELECT columns FROM Employees;

• SELECT * FROM table Employees;

What is a Data Lake?

• A centralized repository for storing large amounts of structured and unstructured data

• A type of database optimized for online transaction processing

• A tool for data visualization and reporting

• A programming language used for data analysis

What is a Data Warehouse?

• A system used for reporting and data analysis

• A type of database optimized for transaction processing

• A software development methodology

• A network security protocol

How does a Data Mart differ from a Data Warehouse?

• A Data Mart is a subset of a Data Warehouse, focused on a specific business area.

• A Data Warehouse is a subset of a Data Mart, focused on a specific business area.

• A Data Mart and a Data Warehouse are the same.

• A Data Mart is used for transactional processing, while a Data Warehouse is used for analytical processing.

What does ETL stand for?

• Extract, Transform, Load

• Execute, Transfer, Load

• Extract, Transfer, Load

• Execute, Transform, Load

What is the first step in an ETL process?

• Extraction

• Transformation

• Loading

• Validation