Cleaning duplicate records with SQL
I needed a way to clean out a MySQL table of records with duplicate email addresses. To do this I used a simple SELECT query inside of an INSERT. INSERT INTO good_users(email) SELECT DISTINCT(email)...
View ArticleMySQL ADDDATE or DATE_ADD
This weekend I needed a couple of MySQL query items that were out of the ordinary, so I thought I would write about them. ADDDATE or DATE_ADD both work the same, but came in very handy. I was...
View ArticleMySQL FIND_IN_SET
I was faced with a field in the database that had a comma separated list of INT’s with a space after the comma. The application searched this field to generate the recordset to display on a web page....
View ArticleGetting differences between dates quickly in PHP or MySQL
I recently needed a way to figure out the difference, in days, between two dates. Here is how I did it. Using PHP: $expireDate = "2006-02-07"; $year = substr($expireDate, 0, 4); $month =...
View ArticleMySqlDump export and MySQL import
To export data as a backup you can’t beat mysqldump. # mysqldump -u username database > database_2007-05-14.sql Then to restore a database you would use: # mysql -u username -p database <...
View ArticleSSH port forwarding/tunneling for MySQL connection
Create an account on the remote MySQL database server. useradd -s /bin/false remote_user mkdir /home/remote_user/.ssh touch /home/remote_user/.ssh/authorized_keys chown -R remote_user:remote_user...
View ArticleMySQL not creating mysql.sock and broken on Hardy Heron
Recently I started receiving errors when I tried to connect to MySQL using command line or PHPMyAdmin. In command line I would get “ERROR 2002 (HY000): Can’t connect to local MySQL server through...
View ArticleGet SSL running on Apache (CentOS)
I was playing with a new virtual server that had CentOS installed on it recently, and wanted to get SSL working for Apache. Since I was only setting up a development server I really didn’t need to...
View ArticleLinux backup using CRON to local directory
As many have pointed out I am on a backup and disaster recovery kick lately. Some would say that it is about time, others are simply glad to see that data is now being backed up. I have found that it...
View ArticleFinding Duplicates using SQL
While migrating old data to a new database schema I was unable to activate a PRIMARY KEY on the legacy_customer_id field because there were duplicates. It turned out that the old application did not...
View Article