Learning Articles

How to Delete a Record in SQL Deleting records in a relational database is a fundamental operation in data management. Whether you’re cleaning up outdated entries or correcting data errors, understanding how to safely and efficiently delete records is essential. This article walks through the process of deleting records in SQL, with code examples using […]

How to Update Data Using SQL Structured Query Language (SQL) is the standard language for managing and manipulating relational databases. Among the many operations SQL supports, updating existing data is one of the most critical and frequently performed tasks. Whether you’re correcting a typo, changing a customer’s contact details, or adjusting stock levels, the UPDATE

How to Insert Data into a Database with SQL An in-depth guide to using the INSERT statement to add data to relational databases Introduction In the world of data-driven applications, interacting with databases is a fundamental task. One of the most common operations you’ll perform is inserting new data into a database. This is typically

How to Write Multiple Joins in SQL When dealing with real-world databases, querying across multiple tables is inevitable. Whether you’re assembling sales reports, user behavior analyses, or inventory summaries, multi-join SQL queries become essential. However, they can quickly become hard to manage or understand if not written thoughtfully. Let’s break down how to write multiple

How to write SQL CROSS JOINs and why they are so dangerous Structured Query Language (SQL) provides several types of joins to combine data from multiple tables. Among these, the CROSS JOIN is arguably the most misunderstood and the most dangerous when used without caution. Learn SQL online For our instructor lead, more in depth

Why understanding the SQL inner join is essential for the analyst In the modern data-driven landscape, analysts are expected to extract insights not just from a single dataset, but by combining information from multiple sources to tell a more complete and accurate story. Whether working with customer databases, financial transactions, user behavior logs, or product

Why you need to know SQL join types In the world of data engineering, analytics, and software development, Structured Query Language (SQL) remains the foundational tool for working with relational databases. Among its many capabilities, JOIN operations are essential when querying across multiple tables. Yet, despite their importance, SQL join types are often misunderstood or

How to group by in SQL Learn how to group and aggregate data effectively using SQL’s GROUP BY clause. When working with databases, it’s often necessary to analyze and summarize data rather than just list it. Whether you’re building reports, dashboards, or performing ad-hoc data analysis, the SQL GROUP BY clause is an indispensable tool.

How to write subqueries in SQL and why you shouldn’t Structured Query Language (SQL) is the bedrock of relational database management and is widely used to manipulate and retrieve data. One of its most flexible and powerful features is the subquery—a query nested inside another SQL query. Subqueries allow for modular, expressive, and readable statements

SQL date formats and how to understand them SQL Server’s handling of date and time values is both nuanced and highly efficient. Behind the scenes, SQL Server doesn’t store dates and times as human-readable strings but as binary integers or floating-point numbers, depending on the data type. Understanding how SQL Server stores these values internally