Learn SQL and Databases the Easy Way
Plain-English guides to SQL, database design and big data, written by a developer who works with databases every day. No jargon, lots of real examples.
Where Do You Want to Start?
New to SQL
Write your first queries and learn to filter, sort and summarise data.
Designing a Database
Build tables that keep your data clean, consistent and easy to query.
Going Further
Speed up queries, protect your data and write smarter SQL.
Latest Articles
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Why Delphi is still a strong choice for ERP and business software: visual forms, built-in database access, native speed, a long life, and the honest downsides. - Delphi Basics: Variables, Data Types, If, Case and Loops Explained Simply
Learn Object Pascal basics in Delphi: variables, constants, data types, strings, if/else, case and for, while and repeat loops, with runnable examples. - ETL vs ELT Explained Simply (With a SQL Transform Example)
What ETL and ELT mean, how they differ, what the transform step looks like in real SQL, full vs incremental loads, and which approach to choose for your data warehouse. - Star Schema vs Snowflake Schema: Fact and Dimension Tables Explained
What a star schema is, how fact and dimension tables work, how to query them with plain SQL, how the snowflake schema differs, and which one to choose for your data warehouse. - OLTP vs OLAP Explained Simply (With SQL Examples)
What OLTP and OLAP mean, how they differ, why heavy reports slow down a live database, and how data moves from one to the other, explained in plain English with SQL examples. - 25 SQL Interview Questions for Beginners (With Answers)
25 SQL interview questions that come up again and again for junior roles, with short answers you can say out loud: joins, GROUP BY, NULL, keys, indexes, ACID, and three classic write-a-query tasks. - What Is Delphi? Install Delphi Community Edition and Build Your First App
A beginner’s guide to Delphi: what it is, what it’s used for, how to install the free Community Edition, and how to build your first Windows app step by step. - Top N per Group in SQL Server: Get the Latest Record for Each Group
How to get the latest record or the top N rows for each group in SQL Server with ROW_NUMBER(), handle ties correctly, and when CROSS APPLY or WITH TIES is the better choice. - SQL DISTINCT and Column Aliases Explained Simply
How SQL DISTINCT removes duplicate rows (and why it applies to every selected column), how it treats NULL, COUNT(DISTINCT), and how to use column and table aliases, including why an alias works in ORDER BY but not in WHERE.