Rants // Fiebert.com

By: Fiebert  09-12-2011

Today I was pulling a query from MySQL and some of my columns were NULL. Now this isn’t the first time I’ve gotten NULL as a result and usually my code has an if statement in there to swap out the NULL values with zero. The problem is this time that I don’t have the option to edit the code after the query has been returned, I need the actual query results to have NULL removed from them. This lead to my discovery of COALESCE.

I have a column SUM(`order-total`) which will return the total dollar amount a user has spent on the website only some users have yet to make any purchases.

COALESCE is used in the following way:


This acts just like str_replace in PHP. You can use COALESCE in any part of your query, it doesn’t only have to be where you specify the columns you want returned.

Other products and services from Fiebert


HTML / PHP / CSS // Fiebert.com

This would return true for every row giving us every single credit card number in the table, and a similar attack would work equally well on an INSERT, DELETE or UPDATE query. PHP has two built in functions addslashes and stripslashes, however you must add slashes to every incoming variable and strip the slashes off of every outgoing variable.


Interesting // Fiebert.com

Write a query for this table to display all user access however if a user is a “Super User”, only display the one row for them demonstrating that they are a “Super User”. I was asked this question a few months ago and liked it due to its simplicity, and how it can be done on paper which is how we’ve been administering our interview tests. Often times a user is given access to multiple packages only to later be given “Super User” access.


The Site // Fiebert.com

First, I’m going to redesign the site to fit more of where I see it going, then I’ll show you my current project cinder, which is basically a random name for the existing project that I came up with right now. Whether or not it worked is another story but I’ve got “The Job” so I think it is about time to repurpose the site. It goes along with the whole computer agnostic trend the web has taken these days.


Database // Fiebert.com

A common issue among dataservers is disk space so it only makes sense to monitor for thresholds so that you can fix an issue before it becomes an emergency. We will construct the remote query dynamically in the code before openrowset and the remote instance will be passed into the instance upon execution. When you must maintain hundreds of machines, space trending is practically a requirement.


Wordpress // Fiebert.com

I’ve totally redesigned / restructured the site from the last theme with high hopes that I can make a solid foundation to build on in the future. I like it because it’s fully extensible and very easy to build on using just the theme alone. I’ve spent a lot of time lately working with wordpress and it’s pretty awesome.