We’ve been taught to round numbers since we were kids. When you round off 1.15 to the nearest tenths, will it be 1.2 or 1.1? Using the SQL ROUND function to answer may confuse you. Later, you will see what I mean.Read More
Are you a T-SQL developer learning the basics of MySQL? Then, one of the things you might want to learn is MySQL CREATE TABLE. Besides, the fastest way to learn a new SQL database platform is by comparing its common functionality and syntax.
That’s what we are going to do today. But the full syntax is a lot. So, we will only cover 5 basic points to get you up and running with MySQL CREATE TABLE.Read More
Having a hard time with SQL UNION? It happens if the results you combined put your SQL Server into a standstill. Or a report that’s been working before pops up a box with a red X icon. An “Operand type clash” error occurs pointing to a line with UNION. The “fire” starts. Sounds familiar?
Whether you’ve been using SQL UNION for a while or just start it out, a cheat sheet or a concise set of notes won’t hurt. This is what you are going to get today in this post. This list offers 10 useful tips for both newbies and veterans. Also, there will be examples and some advanced discussions.Read More
For some people, it’s the wrong question. SQL CURSOR IS the mistake. The devil is in the details! You can read all sorts of blasphemy in the entire SQL blogosphere in the name of SQL CURSOR.
If you feel the same way, what made you come to this conclusion?
If it’s from a trusted friend and colleague, I can’t blame you. It happens. Sometimes a lot. But if someone convinced you with proof, that’s a different story.
We haven’t met before. You don’t know me as a friend. But I hope that I can explain it with examples and convince you that SQL CURSOR has its place. It’s not much, but that small place in our code has rules.Read More
The first time Karl heard of SQL Server CTE was when he was looking for something to make his SQL code easier for the eye. It’s kind of a headache when you look at it. Anton, his concerned colleague, asked him about CTE. Karl thought Anton was referring to his headache. Maybe he heard it all wrong, so he answered, “Of course not.” The funny thing is, he was referring to Chronic Traumatic Encephalopathy, also a CTE – a neurodegenerative disease caused by repeated head injuries. But based on Karl’s response, Anton knew for sure that his colleague was clueless about what he was saying.
What a crazy way to introduce CTEs! So, before you get into the same boat, let’s clarify, what is SQL CTE or Common Table Expressions in the SQL world?
You can read the basics here. Meanwhile, we’ll learn a bit more about what happened in this unusual story.Read More
CROSS JOIN is in the spotlight. This article finishes our small series of SQL JOIN-related publications. If you missed the previous two articles, refer to them as follows:
- Your Ultimate Guide to SQL Join – Part 1: INNER JOIN
- Your Ultimate Guide to SQL Join – Part 2: OUTER JOIN
SQL Server CROSS JOIN is the simplest of all joins. It implements a combination of 2 tables without a join condition. If you have 5 rows in one table and 3 rows in another, you get 15 combinations. Another definition is a Cartesian Product.
Now, why would you want to combine tables without a join condition? Hang on a bit because we are getting there. First, let’s refer to the syntax.Read More
Friend or foe? SQL Server views have been a subject of heated debates when I was in my first year using SQL Server. They said it was bad because it was slow. But how about today?
Are you on the same boat as I was many years ago? Then, join me on this journey to unravel the real deal about SQL views so that you can write them the fastest possible.Read More
Outer join is at the center stage today. And this is part 2 of your ultimate guide to SQL joins. If you missed part 1, here’s the link.
By the looks of it, outer is the opposite of inner. However, if you consider the outer join this way, you’ll be confused. To top that, you don’t have to include the word outer in your syntax explicitly. It’s optional!
But before we dive in, let’s discuss nulls concerning outer joins.Read More
Inner join, outer join, cross join? What gives?
It’s a valid question. I once saw a Visual Basic code with T-SQL codes embedded in it. The VB code retrieves table records with multiple SELECT statements, one SELECT * per table. Then, it combines multiple result sets into a record set. Absurd?
To the young developers who did it, it was not. But when they asked me to evaluate why the system was slow, that issue was the first to catch my attention. That’s right. They never heard of SQL joins. In fairness to them, they were honest and open to suggestions.Read More