Reading Time: 6 minutes When I was first learning how to query databases using T-SQL, I had some very basic questions about the different JOIN operations. I had questions like: “What’s the difference between a JOIN and a LEFT JOIN?” Or “What’s the difference between a regular JOIN and an INNER JOIN?” Or even Continue Reading
UNION and UNION ALL: What’s the difference?
Reading Time: 4 minutes Have you been working with SQL Server for a while, but aren’t really sure what the difference is between UNION and UNION ALL? When I was first learning T-SQL, I wondered this myself. I eventually figured it out, and I was glad to see the difference is very easy to Continue Reading
The IF…ELSE IF….ELSE Statement: Everything You Should Know
Reading Time: 8 minutes The IF…ELSE and the IF…ELSE IF…ELSE structures are the most basic decision structures you should know if you are just starting out with SQL or any other programming/query language. If you are familiar with other languages besides SQL, you will already be familiar with the concept of decision structures. But Continue Reading
HAVING Clause: How it works
Reading Time: 6 minutes The HAVING clause is a very useful tool we can use when querying SQL Server databases. When I was first learning SQL, I had a tough time understanding the HAVING clause. Looking back, I’m not sure what was so difficult to understand. It’s actually very simple. Are you struggling to Continue Reading
GROUP BY clause: A How-To Guide
Reading Time: 9 minutes When you are first learning how to query SQL Server databases, you might find yourself thoroughly confused by the GROUP BY clause. I know I was, for sure. You might ask yourself questions like: “What columns am I allowed to use in the SELECT list?” “Can I put more than Continue Reading
The B-Tree: How it works, and why you need to know
Reading Time: 11 minutes If you had to explain what a B-Tree is and how it works, could you do it? I mean, you know it’s a thing in SQL Server, and it is part of indexes (…somehow), but do you really know what it is? Wood you beleaf me if I told you Continue Reading