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Introduction to SQL Tutorial. Online training course

Structured Query Language (SQL) is essential in modern data management, widely used across various industries. Its universal adoption across industries makes it an essential skill for professionals in data handling roles. DE Academy’s SQL Tutorial course is meticulously designed to cater to a diverse range of learners, from beginners to advanced users, providing them with the tools and knowledge to proficiently manage and manipulate data using SQL.

This course stands out with its unique theoretical knowledge and practical application, ensuring that learners not only understand SQL concepts but are also able to apply them effectively. Targeted at aspiring data analysts, engineers, and anyone interested in data management, this course promises a comprehensive understanding of SQL, culminating in a certification that showcases the learner’s proficiency.

SQL Beginner Lessons

The beginner section of the DE Academy SQL Tutorial course introduces fundamental SQL operators, equipping learners with essential skills for basic data querying and manipulation. This section is designed to provide a practical and comprehensive understanding of how to interact with databases using SQL.

The course begins with an introduction to SQL, focusing on its role in database interaction. Learners will understand the structure and purpose of basic SQL operators, setting the stage for more complex operations in advanced modules.

Key Topics Covered

  • SELECT and FROM Operators. Fundamental to SQL, these operators are used to specify the columns to retrieve and the tables to retrieve them from.
  • LIMIT and OFFSET. These operators control the number of records returned by a query and define the starting point for data retrieval, essential for handling large datasets.
  • WHERE Condition. This operator allows for filtering data based on specific criteria, enabling targeted data queries.
  • Comparison Operators. Essential for creating conditions in SQL queries, comparison operators include equals (=), not equal (<>), greater than (>), less than (<), etc.
  • Logical Operators. These operators, including AND, OR, and NOT, are used to combine multiple conditions in a SQL query, enhancing the specificity of data retrieval.
  • LIKE Operator. Specialized for pattern matching, the LIKE operator is used to search for a specified pattern in a column.

Each topic is accompanied by interactive elements and simulations, ensuring that learners can apply the concepts in practical scenarios. The practice questions, such as crafting basic SELECT queries and using WHERE clauses, reinforce these foundational SQL skills.

SQL Intermediate Lessons

The intermediate section of the DE Academy SQL Tutorial course delves into more complex SQL operations. This stage is crucial for learners who have mastered the basics and are ready to handle more sophisticated data querying and manipulation techniques.

In these modules, learners will explore subqueries, advanced functions, and join operations. These concepts are essential for managing complex datasets and performing detailed data analysis.

Key Topics Covered

  • Subqueries. Learners will understand how to use subqueries, which are queries nested within another query, enabling more complex data retrieval.
  • Subquery with Aggregated Functions. This topic focuses on combining subqueries with aggregated functions like MIN, MAX, COUNT, SUM, and AVG for advanced data analysis.
  • MIN and MAX Operators. These functions are used to find the minimum and maximum values in a dataset.
  • COUNT Operator. Essential for counting the number of rows that match a specified condition.
  • SUM Operator. This function calculates the total sum of a numeric column.
  • AVG Operator. Used for calculating the average value of a numeric column.
  • GROUP BY Clause. This clause groups rows that have the same values in specified columns, often used with aggregate functions.
  • HAVING Clause. Similar to the WHERE clause but used with the GROUP BY clause to filter group data.
  • CASE Statement. A conditional statement that provides if-then-else logic to SQL queries.
  •  INNER JOIN. This join combines rows from two or more tables based on a related column between them.
  • JOIN with WHERE. An advanced technique that combines the JOIN and WHERE clauses for more specific data retrieval based on certain conditions.

The intermediate lessons include hands-on exercises and real-world scenarios, enabling learners to apply these advanced SQL techniques. Practice questions, such as creating complex queries with INNER JOIN and using GROUP BY with aggregate functions, ensure a deep understanding of these intermediate concepts.

SQL Advanced Lessons

The advanced modules of the DE Academy SQL Tutorial course focus on sophisticated SQL functionalities, crucial for handling complex data structures and performing intricate data manipulations. These lessons are designed for learners who are comfortable with intermediate SQL concepts and are ready to elevate their skills.

This section covers a range of advanced topics, from data types and string functions to window functions and data formatting. Mastery of these topics enables learners to efficiently manage and analyze data in diverse scenarios.

Key Topics Covered

  • Data Types. An in-depth look at various SQL data types and their appropriate usage.
  • CAST. This function is used to convert a value from one data type to another, essential for data type compatibility in operations.
  • LENGTH. A function to determine the length of a string.
  • SUBSTRING. Used for extracting a part of a string based on specified positions.
  • CHARINDEX or SUBSTRING_INDEX. Functions to find the position of a substring within a string.
  • TRIM. Removes whitespace from both ends of a string.
  • LEFT & RIGHT. These functions extract a specified number of characters from the left or right of a string.
  • CONCAT. Used to join two or more strings together.
  • UPPER & LOWER. Functions to convert strings to upper or lower case.
  • EXTRACT. Extracts a part of a date, like day, month, or year.
  • COALESCE. Returns the first non-null value in a list of arguments.
  • ROW NUMBER. A window function that assigns a unique number to each row in the result set.
  • LAG. Another window function, useful for accessing data from a previous row without using a self-join.

The advanced lessons include interactive exercises and complex case studies, reflecting real-world data challenges. Practice questions will involve scenarios requiring the use of these advanced SQL functions, ensuring that learners gain hands-on experience and develop a profound understanding of advanced SQL operations.

Practice Questions and Assessments

The DE Academy SQL Tutorial course is enriched with a meticulously curated collection of practice questions at each instructional level, specifically crafted to solidify the learning experience and equip learners with the skills needed for real-world SQL tasks. Each set of questions is tailored to match the complexity and focus of its corresponding course level, ensuring a progressive learning curve.

For beginners, practice questions primarily revolve around basic SQL commands and query formulation, gradually escalating to more nuanced topics like data filtering and basic data manipulation. Intermediate learners tackle scenarios that demand the application of complex queries, joins, and aggregate functions, simulating more challenging data analysis tasks. Advanced level questions push learners to demonstrate proficiency in sophisticated SQL functions, data types, and advanced query techniques.

Complementing these practice questions is a robust assessment process. This comprehensive evaluation method meticulously gauges the learner’s grasp of SQL concepts and their practical application. The assessments include a series of structured tasks and problem-solving scenarios that require the application of the skills and knowledge acquired throughout the course.


DE Academy’s course is meticulously designed for people at every stage of their professional journey, offering a deep, hands-on approach to SQL. Completion of this course ensures that learners are equipped to confidently tackle data management tasks with expertise and proficiency.

To all aspiring data professionals, this is your moment to elevate your skills in a data-driven world. SQL mastery is not just a valuable skill—it’s an essential tool in today’s tech landscape.

Enroll in DE Academy’s SQL Tutorial course now and begin your path to becoming an SQL expert.