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Top 100 SQL Interview Questions and Answers for Every Skill Level

Imagine spending weeks grinding through SQL tutorials, practicing syntax, and refining your queries in your spare time. But when the interviewer throws a complex JOIN + subquery at you, your brain suddenly hits a 404. It happens to the best of us. However, most candidates crash and burn—not because they lack knowledge, but because they prepare like students instead of engineers. They memorize syntax, pray for predictable questions, and freeze the moment they’re asked to think, not recite.

SQL Aggregate Functions: Syntax, Use Cases, And Examples

Without SQL aggregate functions, databases would be nothing more than glorified spreadsheets. These functions—SUM(), COUNT(), AVG(), MIN(), and MAX() —do the heavy lifting in analytics. They process massive datasets, transforming scattered records into clear, usable insights that drive decision-making. But while aggregation simplifies data, it can also slow things down.

Dapper vs. Entity Framework Core: Which One Is Right for Your .NET Project?

“Dapper is pure speed—EF Core is bloated,” or “Dapper is a nightmare—EF Core keeps things scalable.” We’ve all heard it. Both sides make a point, but neither tells the whole story. The real question? Which one will save you from a world of pain six months from now? Dapper gives you raw SQL execution and total control, but you’re on your own when managing transactions, relationships, and migrations.

How to Choose the Right Database for Data Analytics

You start a query, grab a coffee, and come back to… a report that’s still loading. We’ve all been there. When your database wasn’t designed for analytics, even basic reporting can feel painfully slow. Databases aren’t one-size-fits-all, especially when it comes to analytics. The system that works fine for storing and retrieving customer transactions or app data isn’t necessarily built to process complex queries on massive datasets.

Best Data Management Solutions: Features, Pros, and Cons

Data management tools can either be your greatest ally or your biggest headache. Effective data management is the process of controlling and organizing your data assets to ensure their quality, security, and accessibility. The right data management solution simplifies the validation, storage, and processing of your data, transforming it into a reliable resource for accurate analysis, informed decision-making, and regulatory compliance.

What is Data Integration? Definition, Types, Examples & Use Cases

Given the flood of information and emerging cloud and big data technologies, more and more companies are now adopting data integration initiatives to analyze and act on their data more effectively. For modern companies seeking to improve their strategic decision-making and competitiveness, data integration meaning isn’t so simple. What is data integration? We’ll find out in this material!

How to Import Data From Other Software into QuickBooks Online

Struggling with CRM QuickBooks integration? Importing data into QuickBooks Online is essential for building a robust, integrated financial workflow. Whether you’re pulling customer info from external databases, syncing financial records, or automating sales pipeline updates and data migration, it’s a developer’s bread and butter. Yet, QuickBooks Online’s native import features often fall short, with rigid file formats, row limits, and no support for complex data relationships.

Connect to PostgreSQL using EF Core

In this tutorial, we'll walk you through the process of creating an Entity Framework Core model and connecting a.NET console application to a MySQL database. We'll guide you through each step, from setting up your connection to retrieving data from your MySQL tables. Additionally, we'll explain how to install the necessary components, including the dotConnect for MySQL, and demonstrate how to use Entity Developer to generate your model.

Connect to MySQL using EF Core

In this tutorial, we'll walk you through the process of creating an Entity Framework Core model and connecting a.NET console application to a MySQL database. We'll guide you through each step, from setting up your connection to retrieving data from your MySQL tables. Additionally, we'll explain how to install the necessary components, including the dotConnect for MySQL, and demonstrate how to use Entity Developer to generate your model.

Connect to SQLite using EF Core

In this tutorial, we’ll walk you through how to create an Entity Framework Core model and connect.NET console application to SQLite database. We’ll cover how to set up your connection, install the necessary packages, and use Entity Developer to generate a model based on your SQLite database. By the end of this video, you’ll be able to retrieve data from your SQLite tables directly into your.NET console application.

Connect to Oracle using EF Core

In this tutorial, we’ll demonstrate how to create an Entity Framework Core model and connect a.NET console application to an Oracle database. We’ll guide you step by step, showing how to set up your connection, install the necessary components, and use Entity Developer to generate a model based on your Oracle database. By the end of this video, you'll have a functional setup to interact with Oracle tables directly within your.NET console application.

Newly Updated dbExpress, SecureBridge, and EntityDAC With Support for RAD Studio 64-bit IDE, RAD Studio 12.3, and Lazarus 3.8

Looking forward to another milestone in our Data Connectivity powerful product line, which includes—but is not limited to—dbExpress, SecureBridge, and EntityDAC? Here we go with another release that features support for a pioneering RAD Studio 64-bit IDE, as well as the latest versions of RAD Studio and Lazarus. This update also includes new options and highly anticipated demos!

Newly Updated Delphi Data Access Components With Support for RAD Studio 64-bit IDE, RAD Studio 12.3, and Lazarus 3.8

Excited for an enhanced experience with Delphi Data Access Components? The latest release is here, now supporting the most recent versions of RAD Studio and Lazarus along with a bunch of improvements and impressive new features. From now on, Delphi Data Access Components support the newly introduced RAD Studio 64-bit IDE. So, if you have switched to it or are planning to do so, you can use our components without having to worry about possible compatibility issues.

dbForge Tools for Oracle 6.0: A Myriad New Options and Enhancements to Make Your Daily Work Faster and Easier

We’ve got another big update coming your way. This time it’s all about dbForge tools for Oracle, which have received a huge number of new options, functional enhancements, and subtle design tweaks, all of which will work together to make your daily work with Oracle Database exceptionally easy and convenient. Without further ado, let’s see what we’ve got for you today.

Expand Your Connectivity With New ODBC Drivers for Dynamics 365 Business Central, Trello, and ClickUp

Our team is excited to announce the release of three new Devart ODBC Drivers that provide easy access to data stored in Dynamics 365 Business Central, Trello, and ClickUp using the ODBC standard. These Drivers are robust solutions that allow developers, analysts, and business intelligence professionals to connect to live data on cloud platforms and databases directly from any ODBC-compliant application.

Best MySQL GUI Tools for Linux

Linux has a reputation as an operating system for programmers. So, if you are a software developer who designs MySQL-based solutions, chances are high that you will do it on Linux. Thus, it would be great to have a MySQL IDE for Linux to simplify the work. But the question arises: is there an appropriate Linux DB tool for MySQL with a GUI?

New in SSIS Data Flow Components 3.1: Optimized Performance & Expanded API Support

We are thrilled to announce a major release of our SSIS Data Flow Components, powerful tools designed to simplify the ETL process within SQL Server Integration Services (SSIS) packages. This update brings significant enhancements, including improved performance, support for new server versions and APIs, and the addition of new objects and properties to existing components.