MySQL's slow query log is a key component in your MySQL administration setup. Whilst normal logging can help you in terms of tracking down issues with your database system, the slow query log can help you track down issues in your database setup before they become problematic.
Using frameworks to handle the authentication of your PHP application is perfectly fine to do, and normally encouraged. They abstract away all of the complexity of managing users and sessions that need to work in order to allow your application to function.
I needed to create a query that did a case insensitive search using the LIKE command in MySQL and I quickly realised that in order to do this I would need to alter both the parameter and the table data to be the same case. This can be done by using the MySQL UPPER() command on the table data and the strtoupper() PHP function on the input data.
Connecting to a MySQL database in PHP is usually not a difficult thing to do, in fact it is one of the first things that many tutorials will go though. However, there are certain curcumstances that require more information than the standard host, password and username details.
Today I needed to grab some data from a table where there was more than one occurrence of a string within another string. Basically, I needed to find all URL's from a table that were more than 3 levels deep (i.e. with 3 slashes), but realised there wasn't a function to do this in MySQL.
As part of debugging a bit of code I needed to know the longest possible field lengths that a record contains. You might need to know this if you are performing a database migration. The following query returns a field, along with the length of the string, and orders the results by the number of characters in that string.