(Peter Gulutzan) The MySQL manual says: “In standard SQL, a query that includes a GROUP BY clause cannot refer to nonaggregated columns in the select list that are not named in the GROUP BY clause.”

(Dan Langille) Earlier today, I wrote about a fix which broke search. At the end of that post, I mentioned a few things which needed to be done to fix up the broken relationships.

(Morgan Tocker) We are considering enabling the SQL mode ONLY_FULL_GROUP_BY by default in MySQL 5.7. Here is a quick example to demonstrate how this change will impact you:

(Norvald H. Ryeng) Since union queries were introduced in MySQL 4.0.0, they have been processed by executing each part of the union and adding the result to a temporary table. Then a final query block is executed that, if needed, filters out duplicates, do global ordering and limit the number of out

(Noel Herrick) Designing database tables for many customers is a surprisingly foreign concept for some programmers. I’ve been in interviews where a programmer will sketch out a normal object model, and then proceed to suggest that for the database, each customer has their own set of tables, each pre

(Nilnandan Joshi) There are many blog posts already written on topics related to “MySQL server memory usage,” but nevertheless there are some who still get confused when troubleshooting issues associated with memory usage for MySQL. As a Percona support engineer, I’m seeing many issues regularly rel

(Sveta Smirnova) As author of MySQL JSON functions I am also interested in how development goes in another parties. JSON functions and operators in PostgreSQL, indeed, have great features. Some of them, such as operators, I can not do using UDF functions only. But lets see how these functions are in

(Eric Bergen) Configuring the character set for MySQL is confusing. It is so confusing that there are roughly 25 different places to configure a character set. Don’t believe me? Add them up. The real number may be closer to 30. I realize a lot of this is due to the age of MySQL and the extent of it’

(Noel Herrick) I’ve covered some strange default behavior around nulls in MySQL. There’s another nuance to this issue: you can still insert rows without specifying values for not null columns. MySQL will helpfully give you a default value (this is not really helpful – true help would be a quick fail

(Mayank Prasad) This is the very first post in the series of Performance Schema Implementation Internals. This series is for MySQL Developers to understand implementation of Performance Schema.