Career Development

15 SQL Skills You Need to Know in 2024

Data engineers and other technical professionals will still need to know SQL in 2024 in order to handle and manipulate data effectively. Advanced SQL skills are becoming more and more necessary as the need for data-driven decision making increases. Whether you’re an experienced professional or an aspiring data engineer, learning SQL can greatly improve your employment prospects. This article outlines the top 15 SQL skills you’ll need to succeed in the industry and maintain your competitive edge. These abilities are essential for managing the ever-changing data world, from simple searches to sophisticated analytics and integration with contemporary technology. To help you stay ahead in your career, The Data Engineer Academy is committed to providing these skills through in-depth instruction and practical tutorials.

Fundamental SQL Skills

Basic SQL queries

Any profession involving data engineering starts with an understanding of basic SQL queries. You may efficiently access and filter data from databases by becoming proficient with the SELECT, FROM, and WHERE clauses. These basic processes are essential for daily tasks like basic data analysis, report generation, and valuable insight extraction.

Simple SQL queries can be used to generate sales reports in an e-commerce platform or to extract user data from a web application.


SELECT name, age FROM users WHERE age > 30;

You may find interactive tutorials at Data Engineer Academy that walk you through the fundamentals of SQL queries and help you build a strong foundation.

Joins and subqueries

Joins and subqueries are key to merging data from several tables and streamlining intricate searches. Gaining proficiency with subqueries, LEFT JOIN, RIGHT JOIN, and INNER JOIN enables you to effectively integrate and analyze data from many sources.

These abilities come in handy when analyzing purchase activity in a retail database by merging order and customer data.


SELECT orders.order_id,

FROM orders

INNER JOIN customers ON orders.customer_id = customers.customer_id;

SELECT * FROM users WHERE id IN (SELECT user_id FROM orders WHERE total > 100);

Aggregate functions

For data analysis and summarization, aggregate functions such as COUNT, SUM, AVG, MIN, and MAX are employed. These features facilitate the production of insights such as average transaction values, total sales, and the identification of extreme values.

To offer summary statistics, aggregate functions are frequently used in business intelligence and reporting.


SELECT COUNT(*), AVG(salary), MIN(salary), MAX(salary) FROM employees;

Courses at the Data Engineer Academy cover how to use aggregate functions to generate insightful reports, ensuring you can derive meaningful insights from your data.

Advanced SQL Skills

Window functions

The window functions ROW_NUMBER(), RANK(), PARTITION BY, and ORDER BY are essential for carrying out intricate computations over groups of table rows while keeping the row-level information intact. These functions come in quite handy when doing moving averages, ranking data, and computing running totals.

Window functions are often used to create comprehensive, iterative calculations over a dataset without condensing it into a single output row in data analysis and reporting.


SELECT name, salary, 

       RANK() OVER (PARTITION BY department ORDER BY salary DESC) as rank

FROM employees;

CTEs (Common Table Expressions)

By enabling you to build temporary result sets that can be referenced within a SELECT, INSERT, UPDATE, or DELETE statement, Common Table Expressions (CTEs) make complex queries simpler. CTEs improve SQL code’s readability and maintainability, which facilitates management and debugging.

CTEs are frequently employed in recursive inquiries and hierarchical data processing, where they are especially helpful in decomposing intricate searches into smaller, easier-to-manage components.



    SELECT product_id, SUM(sales) AS total_sales

    FROM sales

    GROUP BY product_id


SELECT product_id, total_sales FROM Sales_CTE WHERE total_sales > 1000;


Indexing is an effective way to improve database query performance. The time it takes to retrieve records can be greatly decreased by building indexes on database columns, especially for huge datasets.

This function is essential for maximizing query speed in applications like search engines and highly trafficked websites that handle massive amounts of data and demand quick retrieval times.


CREATE INDEX idx_user_lastname ON users(lastname);

Transaction management

Maintaining data integrity and making sure database operations are successfully finished depend on transaction management. You can maintain consistency and gracefully handle mistakes by controlling transactions with the COMMIT, ROLLBACK, and SAVEPOINT commands.

In financial applications, it’s critical to make sure that every step of a transaction is finished correctly before committing changes to the database. This is where transaction management comes in.



UPDATE accounts SET balance = balance - 100 WHERE account_id = 1;

UPDATE accounts SET balance = balance + 100 WHERE account_id = 2;


Learn transaction management through hands-on exercises that simulate real-world scenarios at Data Engineer Academy.

Stored procedures and functions

Reusable SQL code blocks can be encapsulated using stored procedures and functions, which helps to automate operations and encourage code reuse. They increase the effectiveness of your SQL queries and help to simplify database operations.

These are frequently utilized in enterprise applications for carrying out standard database operations, validating data, and implementing business logic.


CREATE PROCEDURE UpdateEmployeeSalary @EmployeeID INT, @NewSalary DECIMAL



    UPDATE employees SET salary = @NewSalary WHERE id = @EmployeeID;


EXEC UpdateEmployeeSalary 1, 60000;

Error handling

TRY…CATCH blocks provide robust error handling, which is essential for preserving data integrity and guaranteeing smooth operations. You may better control your SQL processes by catching and managing exceptions with the help of appropriate error handling tools.

In applications like online transaction processing and financial systems, where data integrity and reliability are crucial, error management plays a vital role.



    UPDATE employees SET salary = -5000 WHERE id = 1;



    PRINT 'An error occurred: ' + ERROR_MESSAGE();


The Data Engineer Academy is committed to helping you master these advanced SQL skills through comprehensive courses and practical tutorials.

Modern SQL Skills

NoSQL integration

The ability to integrate SQL with NoSQL databases has become increasingly important as the variety of data kinds and storage options increases. Knowing how to deal with NoSQL and SQL databases enables you to take use of their respective advantages, resulting in more effective and flexible data management.

NoSQL integration is utilized for scalable and flexible data solutions in contexts where structured and unstructured data coexist, such as when relational database management systems (RDBMS) are combined with document stores like MongoDB.


SELECT * FROM mongo_collection('db.collection_name') WHERE sql_condition;

Big data and SQL

Large-scale dataset processing has become commonplace with the advent of big data technologies like Hadoop and Spark. Data engineers may efficiently do complicated data analysis and transformations on large datasets by using SQL with these big data technologies.

Large-scale data processing is necessary for analytics, reporting, and machine learning in sectors like banking, healthcare, and e-commerce, which is why SQL with big data technology is crucial.


SELECT * FROM hadoop_table WHERE condition;

Data Engineer Academy’s courses include practical examples and projects that demonstrate SQL’s role in big data environments, ensuring you gain hands-on experience.

Data security and compliance

Ensuring data security and compliance with laws like the CCPA and GDPR is essential. When it comes to putting access controls, audits, and data encryption into practice, SQL is a key component.

In order to guarantee that customer data is safeguarded and standards are followed, data security and compliance skills are essential in industries handling sensitive information, such as banking and healthcare.


GRANT SELECT ON employees TO data_analyst;

Graph databases and SQL

Because graph databases can represent intricate relationships, they are growing in popularity. You can use graph theory for applications such as fraud detection, recommendation systems, and social network analysis by using SQL to query graph databases.

Graph databases are employed in applications like recommendation engines, fraud detection systems, and social media platforms where the relationships between data pieces are just as significant as the data itself.


SELECT * FROM graph_table WHERE MATCH (n)-[r]->(m);

Machine learning integration

An important part of the data science pipeline is preparing data for machine learning applications. You can efficiently clean, transform, and aggregate data using SQL for data preparation, resulting in high-quality inputs for machine learning models.

Data science initiatives across a variety of industries, such as anomaly detection, consumer segmentation, and predictive analytics, use SQL for machine learning integration.


SELECT feature1, feature2, label FROM dataset WHERE condition;

Hands-on projects at Data Engineer Academy teach how SQL is used for data preprocessing in machine learning, ensuring you are well-equipped to contribute to data science initiatives.

Cloud SQL services

As more businesses transition to cloud-based solutions, proficiency with SQL in cloud settings such as AWS RDS, Google BigQuery, and Azure SQL Database is becoming imperative. Large data volumes are made easier to handle by these services’ scalable, adaptable, and managed database solutions.

Modern IT infrastructures leverage cloud SQL services to maintain databases without the burden of hardware management, offering scalable solutions for small and medium-sized businesses.


SELECT * FROM `project.dataset.table` WHERE condition;

You can enhance your career and be ready to face the challenges of the data-driven world of today by becoming an expert in NoSQL integration, big data technologies, data security, graph databases, machine learning integration, and cloud SQL services.

How to Master SQL Northstar for your Data Interview

Wrap Up

With new technology and the increasing need for data-driven decision-making, SQL is still developing. Keeping aware of the most recent SQL innovations and upcoming trends is essential for preserving a competitive edge as the data landscape shifts. SQL’s capabilities will be further enhanced by advancements in big data, cloud computing, machine learning, and data security, making it a vital tool for data engineers.

It’s imperative to keep learning and developing these SQL abilities in order to remain competitive in the quickly developing industry of data engineering. You may develop these skills with the aid of the many courses and hands-on tutorials provided by the Data Engineer Academy. Begin learning today to succeed in your work and make a meaningful contribution to your organization’s