Some Post Content Does Not Show Up In DB Search

WordPress store the content from the editor inside the table post_content. But if you use additional plugins for your editor it is possible to store on different places, like custom tables and also in post_meta, really popular for third plugins to store date there use the meta API.

Small hint, maybe you should use a a plugin for search/replace in the database if you not so familiar with the search about all tables. Makes easier to find the right point there store your data.