SQL basics – your path to more efficient tests

If you are in the software testing field, you should know that database and SQL are not only the domain of database administrators or back-end developers. In the era of digital transformation, databases are key, and SQL is an essential tool for managing and understanding them. In this article we will look at the basics of SQL, its connection with databases, show basic SQL statements and talk about MS SQL.

Database: data repository

The database is where all the data is stored. It’s a comprehensive system that allows you to store, retrieve, edit and manage information. If you are testing an application that interacts with a database (and most of them do), you need to know how data travels between the database and the application and how to interact with the database – this gets to the heart of SQL.

SQL: database language

SQL, which stands for Structured Query Language, is a standardized programming language used for working with databases. It allows you to perform various data operations such as Create, Read, Update, Delete (CRUD) in a very efficient and flexible form.

Using SQL in testing

The use of SQL (Structured Query Language) in software testing is crucial to verify the integrity and accuracy of data that is essential for the correct functionality of applications. Below are some of the main areas where SQL is used in the context of software testing:

Data verification

  • SQL statements allow testers to verify that data in the database is correctly stored, updated or deleted as required.
  • The tester can create SQL queries to check data consistency between different database tables and systems.

Data manipulation

  • The tester can use SQL statements to create, update, or delete data to verify how the system handles different data scenarios.
  • Using SQL, it is possible to simulate various data conditions that may be difficult to achieve in other ways.

Data analysis

  • SQL enables analysis of large volumes of data, which is useful in identifying problems or trends that could affect system performance and reliability.
  • The tester can use SQL statements to obtain useful statistics and metrics to help improve the quality of the software.

Performance testing and optimization

  • SQL statements can be optimized for faster performance, which is crucial when testing database operations and system performance.
  • The tester can identify and remove bottlenecks in database operations, contributing to overall system performance and scalability.

Automation of testing

  • Integration of SQL statements into automated test scenarios enables efficient and accurate testing of database operations.
  • SQL statements can be used to validate test results automatically and to generate test reports.

Monitoring and logging

  • SQL can be used to create and analyze logs and monitoring data, which is important for detecting problems and improving software quality.

Bonus: Collaboration with the team

When you understand SQL and databases, you become a more valuable member of the team. You can communicate effectively with developers, analysts and database administrators. You understand the technical details that are critical to the successful completion of a project.

Few things are as universally applicable in software testing as knowledge of SQL and databases. This knowledge will give you a glimpse under the hood of the applications you’re testing and allow you to develop skills that go beyond clicking buttons and tracking output.

SQL syntax and basic commands

SQL works with entities called tables, which are made up of columns and rows. The columns represent different attributes (e.g. name, age, address), while the rows represent individual records.

SQL has a relatively simple and easy to read syntax. Here are some basic rules:

  • Commands are usually written in capital letters, for example SELECT, FROM, WHERE.
  • SQL is case-insensitive, but the standard convention is to use uppercase for statements and lowercase for table and column names.
  • Commands are terminated with a semicolon.

Now imagine that you are testing the database system of a medium-sized company, which contains a table of employees. What basic SQL statements would you use in real test scenarios?


This is probably the simplest and most used command. You can use it to select data from the table.

FROM Zamestnanci;

In this case, you would get a complete list of all employees.


If you need to add new data to the database, you use the INSERT command.

INSERT INTO Zamestnanci 
(ID, Meno, Priezvisko, Pozicia) 
(5, 'Jozef', 'Novák', 'Developer');

This will add a new employee named Jozef Novák to the position Developer.


The UPDATE command allows you to change existing data.

UPDATE Zamestnanci 
SET Pozicia='Senior Developer' 

Change the position of the employee with ID 5 to ‘Senior Developer’.


As the name implies, the DELETE command deletes data from the database.

DELETE FROM Zamestnanci 

You delete an employee with ID 5.


This statement is a bit more complex and is used to join multiple tables.

SELECT Zamestnanci.Meno, Oddelenia.Nazov 
FROM Zamestnanci 
JOIN Oddelenia 
ON Zamestnanci.OddelenieID = Oddelenia.ID;

You’ll get a list of employees along with the name of their department.


The command is used to group data according to a certain criterion.

SELECT Pozicia, COUNT(*) 
FROM Zamestnanci 
GROUP BY Pozicia;

In this case, you get the number of employees grouped by their positions. For example, how many developers, analysts, etc.

There are many other SQL commands and functions that allow you to perform more complex database operations. For a deeper understanding and to get a complete list of SQL commands, we recommend you to read the official documentation.

Microsoft SQL Server (MS SQL)

Microsoft SQL Server, often referred to as MS SQL or simply SQL Server, is a relational database platform from Microsoft. It is one of the most popular database solutions on the market and is known for its robustness, scalability and wide range of functionalities.

Basic MS SQL Functions

  • ACID Compatibility: supports transactions that meet ACID (Atomicity, Consistency, Isolation, Durability) rules.
  • Security: offers extensive security options including authentication, authorization and data encryption.
  • Scalability: can be extended to multiple servers and highly available solutions.
  • Integration with other tools: better integrated with other Microsoft products, such as Windows Server, Active Directory, and the .NET framework.

Versions and Editions

There are several editions of MS SQL Server, including:

  • Express: free version with limited features and performance, ideal for small applications.
  • Standard: target version for medium-sized enterprises.
  • Enterprise: the most robust version that offers all available features and is designed for large enterprises.

Language support

  • MS SQL uses its own version of the SQL language called T-SQL (Transact-SQL), which extends standard SQL functions with procedural programming and local variables.

SQL Server Management Studio (SSMS)

SQL Server Management Studio (SSMS) is an integrated solution that makes it easy for you to manage, access, and use elements in MS SQL Server databases. If you’re a software tester, it’s a tool that allows you to comfortably interact with the database system you’re testing.

SSMS offers you a wide range of tools and features that you can use in test scenarios. These include:

  • Querying: you can execute SQL statements in different formats, whether you want to retrieve, modify or delete data.
  • Views of the scheme: You have the ability to view and analyze the structure of the database, which helps you better understand how the data is stored and processed.
  • Data management: you can easily manipulate test datasets with the data import and export tools.
  • Analytical tools:SSMS provides you with performance analysis and other diagnostic features to help you identify problems or performance limitations.

What are the benefits for testers?

  • Efficiency: thanks to the graphical interface and rich functionality, you can quickly and efficiently test the database without having to write complicated scripts.
  • Accuracy: features such as point-in-time recovery, transaction tracking and logging help you run tests with high accuracy.
  • Flexibility: you can adapt your working environment to your needs, allowing you to better focus on specific aspects of testing.

SQL courses and education

There are several course options in Slovakia for gaining knowledge and skills in SQL. Here are some of them:

  1. IT Academy:in Bratislava offers a SQL course for beginners, where you can attend day, evening or weekend classes. The course is designed for anyone who wants to learn how to work with SQL databases.
  2. IT LEARNING SLOVAKIAA: Offers SQL database training courses, which are divided by platform into MS SQL, MY SQL, ORACLE courses. The courses are designed for developers and analysts who work with databases or develop database applications.
  3. Skillmea: Offers an online course in SQL data analysis for beginners. The course focuses on the essential knowledge needed for work or personal purposes in the areas of data analytics in SQL, big data, BI, DWH and business insights.

You can also find a lot of material about SQL on the Internet, here are some online sources of documentation and tutorials that can guide you through learning SQL:

  1. Microsoft SQL Server:
    Technical documentation to help you get started, administer, develop, and work with SQL Server and related products.

  2. MySQL
    : Documentation for MySQL that includes a reference guide and release notes for MySQL 8.0.

  3. Oracle
    SQL Developer
    Description : Documentation for Oracle SQL Developer, a free graphical tool that increases productivity and simplifies database development tasks. With this tool you can browse database objects, run SQL statements and SQL scripts, edit and debug PL/SQL statements, manipulate and export data, or view and create.

  4. W3Schools SQL Tutorial
    : A tutorial that shows you how to use SQL in various database systems such as MySQL, SQL Server, MS Access, Oracle, Sybase, Informix, Postgres and others.


In today’s IT world, a basic knowledge of SQL is more of a necessity than an advantage for a tester. We hope this article will help you better understand why this is so, and how to deal with it. The basics of SQL are not complicated at all and with a little practice you will quickly get the hang of it.

If you speak German and are an IT tester, check out our employee benefits and respond to job offers.

About the author

Katarína Kučáková

Software Test Engineer

Moja cesta k testovaniu softvéru sa začala v roku 2019 až po štúdiu ekonómie a pracovných skúsenostiach v iných odvetviach. To mi pomohlo vnímať IT svet v rôznych súvislostiach. Ten totiž ponúka neustále nové výzvy, pre ktoré rada hľadám riešenia. Obľubujem oddych pri čítaní, turistiku alebo lyžovanie. LinkedIn

Let us know about you