If you need to provide a full text search facility then you probably want to implement a search engine. You can then index the text from your database records and search using the full facilities of the search engine rather than SQL. The search results are identified by the SQL primary key so that the result records can be retrieved.

Indexing a SQL database is easy to do since you can update the fulltext index from using database triggers (if supported) or frequent scheduled processes. This technique is widely implemented by commercial eCommerce sites.

I do this pretty regularly using a large and expensive commercial product but there are numerous open source examples ready to use. Check out the Searchtools.com site for more information.