DataGeek.blog

January 31, 2023 Featured

MySQL’s “partial” Group By

This is one area that was not a surprise to me coming from Db2 to MySQL, as I’ve had to deal with people confused in the other direction for years. Essentially, MySQL allows a syntax for GROUP BY that Db2 and most RDBMSes do not allow.… Read the rest

January 26, 2023 Featured

Using ChatGPT to Write SQL

Working in technology, I’ve heard a number of things about ChatGPT from various news sources.

I was particularly interested hearing some teachers saying it was the end of being able to properly detect students cheating when writing papers. Then I heard a teacher talking about how this was the new ‘calculator’ that teachers need to learn how to leverage in their curriculums.… Read the rest

December 6, 2022 Featured

Comparing Db2 and MySQL: Naming Objects and Reserved Words

Every RDBMS has areas where the differences from other RDBMSes are noticeable, and this is one of them between Db2 and MySQL. Most RDBMSes have quirks to the way SQL is written, and this is certainly true of Db2 where some things were there before the SQL-92 standard or other standards existed.… Read the rest

December 1, 2022 Featured

Db2 Basics: Getting Data Out of Db2

One of the things that learning a new platform (MySQL) has taught me is just how critical the most basic topics are, so I thought I’d do an overview of how to get data out of a Db2 (on Linux, Unix, or Windows) database.… Read the rest

November 8, 2022 Featured

Comparing Db2 and MySQL: Explain

The goal of this article is to to take one query and use the explain facilities of Db2 to walk through it, and then do the same with MySQL, and then show some of the optimizations I might make for the query and why.… Read the rest

November 3, 2022 Featured

Comparing Db2 and MySQL: NULL in Indexes

I’ve been spending some time working with indexes as I learn MySQL, and there were a few things I thought were were worth mentioning. As always, I’m writing from my own knowledge with deep experience in IBM DB2, and as a learner when it comes to MySQL.… Read the rest

October 27, 2022 Featured

Comparing MySQL and Db2: Table and Index Structure

I’ve spent some time understanding how MySQL structures tables and indexes, and wanted to share what I’ve learned. This is not the structure as created in the CREATE TABLE or CREATE INDEX statements, but how that data is generally structured on disk, both logically and physically.… Read the rest

October 13, 2022 Featured

The Most Shocking Differences I’ve Seen Between Db2 and MySQL (so far)

As I’ve been learning the details of MySQL, there have been a lot of similarities with Db2, and a number of differences. Some of those differences have been things I was expecting, while others have been a bit more shocking. If others are making the transition from Db2 to MySQL (using InnoDB) or vice versa, or are supporting both, maybe something here will help.… Read the rest

September 15, 2022 Uncategorized

SQL Anti-Pattern: Indexing Every Column Individually

Indexes are magic, right? Add one and magically the performance of a query improves.

Well, not really. Each index has a cost, and thoughtful multi-column indexes will go a lot further than individual indexes. Let’s dig into the details.

What an Optimizer Does

Relational databases require queries to specify what data they want returned with no specification of where that data is on disk.… Read the rest

September 8, 2022 Uncategorized

RDBMS Concept: Buffer Pool

One of the things that learning a new RDBMS is teaching me is that there are some concepts that are common to RDBMSes. It is helping me to identify some of those concepts, and I learn a lot from the similarities and differences.… Read the rest

August 30, 2022 Featured

DBA Perspective: Open Source vs. Proprietary RDBMS

Moving from being a DBA on a proprietary RDBMS for 20 years to working on an open source RDBMS is teaching me a lot of lessons. Many of them are lessons I expected – remembering how and when to ask for help, getting used to not being expected to be the expert on everything, and technical details around how MySQL does things differently.… Read the rest