simple and effective, great for HTTP to HTTPS conversion

This plugin is simple and effective. Set up your search terms, select the tables you want to search, then do a dry run to see how many changes will result. When you’re confident that you have the right terms, uncheck the dry run box and run the query for real.

I’ve been using this plugin on sites that we’re converting to HTTPS and it works really well. After changing the site URL and WordPress URL in General Settings, use this plugin to search for http://yourdomain and replace with https://yourdomain in the options, posts and post_meta tables. This takes care of internal HTTP links and prevents mixed content warnings in the visitor’s browser.