SQL Essentials Practice Exam

SQL Essentials Practice Exam

About SQL Essentials Exam

SQL (Structured Query Language) is a powerful tool used to interact with databases by retrieving, updating, and managing data. It is widely used in data analysis, software development, and backend programming. Understanding SQL helps professionals work with relational databases and execute queries efficiently. In this course, you will learn how to create databases, insert and extract data, filter information, and perform complex data operations. By the end of the course, you will have the skills needed to write SQL queries for technical interviews and real-world job tasks.

Skills Required

• No prior knowledge of SQL or databases is needed.
• Basic familiarity with Python is recommended but not required.
• A willingness to practice writing SQL queries.

Knowledge Area

This course will help you:

• Understand relational databases and how they store data.
• Write SQL queries to retrieve, filter, and modify data.
• Use SQL functions, including aggregation, joins, and subqueries.
• Work with different SQL commands such as SELECT, INSERT, DELETE, and UPDATE.
• Optimize queries to improve performance using window functions.

Who should take This Course?

• Beginners who want to learn SQL from scratch.
• Developers who need to integrate SQL databases into their applications.
• Data analysts looking to extract, analyze, and manipulate data using SQL.
• Anyone preparing for SQL interviews or technical job roles.

Course Outline

The SQL Essentials Exam covers the following topics - 

Domain 1 - Introduction to Databases and Course Setup

• Learn the basics of relational databases and how data is structured.
• Understand schemas and data types in SQL.
• Set up a PostgreSQL server on Mac and Windows for local development.
• Choose an SQL editor (Postico, DataGrip, or CLI) to write and execute queries.
• Learn how to create and remove databases using SQL commands.

Domain 2 - Working with Databases, Tables, and Queries

• Create schemas to organize data.
• Define and modify tables to store structured information.
• Alter tables by adding or modifying columns.
• Use enumerated types to store fixed sets of values.
• Insert new records into a database.
• Run SQL scripts to automate database tasks.
• Extract data using SELECT queries.
• Create tables based on query results.
• Use aliases and ordering to organize query outputs.

Domain 3 - Filtering Data and Arithmetic Operations

• Perform conditional filtering using direct comparisons (e.g., =, >, <).
• Group conditions using AND, OR, and NOT operators.
• Filter null values to refine results.
• Create new columns dynamically using arithmetic operations.
• Convert data types within SQL queries.
• Apply logic statements for advanced filtering.

Domain 4 - Working with Dates, Times, and Data Manipulation

• Manipulate string data by extracting and formatting text.
• Retrieve specific positions within strings.
• Concatenate, replace, and transform string values.
• Work with date and time functions for timestamp operations.
• Calculate time intervals and perform date-based calculations.
• Use SQL comments to document queries for better readability.
• Apply aggregation functions like SUM, COUNT, AVG, MIN, and MAX.
• Group and filter aggregated data using GROUP BY and HAVING clauses.

Domain 5 - Joins, Unions, and Subqueries

• Perform INNER JOINS to connect related data from multiple tables.
• Explore LEFT JOIN, RIGHT JOIN, and OUTER JOIN to retrieve missing data.
• Use SELF JOINS to compare data within the same table.
• Combine query results with UNIONS for advanced dataset manipulation.
• Execute subqueries to filter and retrieve specific data.
• Understand Common Table Expressions (CTEs) for organizing complex queries.

Domain 6 - Window Functions for Query Optimization

• Learn how window functions differ from aggregation.
• Use row numbering and ranking functions for sorting and comparison.
• Apply window functions to access other rows within a dataset.
• Implement NTILE to distribute rows into groups for advanced analytics.
• Analyze query performance and optimize execution for efficiency.

Domain 7 - Hands-On SQL Exercises

• Exercise 1: Writing basic queries to retrieve and filter data.
• Exercise 2: Creating and modifying tables using different SQL commands.
• Exercise 3: Working with string functions and date manipulations.
• Exercise 4: Using joins, unions, and subqueries to extract insights.
• Exercise 5: Implementing window functions for advanced analysis.