5 Best Big Data and Data Engineering Books for SQL Users
The best books on big data, data warehousing and data engineering for people who already know SQL, from Fundamentals of Data Engineering to Learning Spark.
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.
5 Best SQL Performance Tuning Books (Including 2 Free Ones)
The best books for SQL performance tuning: indexes, execution plans and troubleshooting slow SQL Server queries. Two of them are free ebooks.
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.
T-SQL Fundamentals (4th Edition) Review: Is It the Best SQL Server Book?
An honest review of Itzik Ben-Gan’s T-SQL Fundamentals, 4th edition: what it covers, who it is for, its strengths and weaknesses, and whether you should buy it.
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.
SQL Server Parameter Sniffing: Why a Query Is Fast in SSMS but Slow in the App
Why the same SQL Server procedure is fast for one value and painfully slow for another, or fast in SSMS but slow in your application, how to confirm it is parameter sniffing, and six fixes with when to use each.
Running Totals in SQL Server: Cumulative Sums and Running Balances
How to calculate a running total and a running account balance in SQL Server with SUM() OVER, reset it per month or account, and avoid the two mistakes that give wrong or slow results.
SQL LIKE, IN and BETWEEN Explained Simply
Search text with LIKE, match a list with IN and filter ranges with BETWEEN, with simple examples, the NOT IN NULL trap and the date BETWEEN mistake that hides rows.