(Peter Zaitsev) JOINs are expensive and it most typical the fewer tables (for the same database) you join the better performance you will get. As for any rules there are however exceptions.
Tag: Open Source
PostgreSQL Pg_dump Pg_Restore Cheatsheet Overview
(Leo Hsu and Regina Obe) Backup and Restore is probably the most important thing to know how to do when you have a database with data you care about.
SQL Standards, ANSI committees, and Sun
(Peter Gulutzan) The two big developments in the SQL world this summer are the pending arrival of the SQL:2008 ANSI standard, and my (Peter Gulutzans) attendance on Suns behalf at an ANSI meeting. Okay, I concede that the events have unequal importance, but sometimes I slip in a bit about personal i
A fast, single pass method to calculate the median in MySQL
(Roland Bouman) After stepping off of the GROUP_CONCAT() solution for calculating quantiles I figured it would be nice to find a better way to calculate the median too.
Good SQL Querying
(Sheeri Cabral) By Good SQL Querying, I am not referring to how to make your queries more perfomant. I am about to go on a mini-rant about how to make readable and self-documenting SQL queries.
MySQL Percentile aftermath: Calculating all quantiles
(Roland Bouman) Are you getting fed up yet with my posts on calculating percentiles? Well, I’m sorry but I’m not quite finished.
How SHOW SLAVE STATUS relates to CHANGE MASTER TO
(Peter Zaitsev) As you probably know MySQL Replication (statement based) works by fetching statements from MASTERs binary log and executing them on the SLAVE. Since MySQL 4.0 this process is a bit more involved having events passing via relay logs on the Slave which also means there are two replicat
Group by ORDER by Optimization part II
(Dathan) In my previous blog post I talk about GROUP BY and ORDER BY optimizations. A member asked a great question that I’d like to share with everyone.
Calculating Percentiles with MySQL, Round 2
(Roland Bouman) My previous post on calculating percentiles with MySQL generated some comments and good discussion. In particular, I got some very interesting comments from Vladimir.
Creating an Online Storefront in PHP, MySQL and Apache, Part 3
(Julie C. Meloni) As you might have guessed, the next item on the task list is to build that showtopic.php file to show the topics postings. Listing 21.5 does just that. In this listing, lines 36 check for the existence of a value for topic_id in the GET query string. Because you intend to show all