Ever use GROUP BY and realize you can't choose the values (non-aggregate) to be returned which are not specified in the GROUP BY? Here's how.

Ever use MySQL to query where a field is false and you didn't get the full set of data you expected? The problem may be null in your field.

Using the Javascript function parstInt() on the strings '08' and '09' returns 0. This is due to the design of parseInt. All numbers starting with 0 are assumed to be in octal.

mysqldump is a command line program used to export data from MySQL. The data is usually exported to a file and is in the form of MySQL queries. mysqldump can be used to backup a database and its data.

tar is a file format used for archiving, as well as a Unix program to handle tar files. A tar file is often referred to as a tarball and have the extension .tar.gz, or tgz.