Full text search on multiple tables

Question

MySQL

Essence:
There are several tables: news, pages, products, and so on.
The task is to search for a phrase in these tables in several fields (title, text, long text)
and sort by relevance

How is it better to implement?
While I see options to unite tables by means of union.
Or create a special table for searching where to synchronize all the texts. At the same time clean from tags.
Several requests will not work, as I understand it, because everyone will have their own sorting by relevance.

I would like to do without complex solutions like sphinx. (Not that task.)

Answer 1

Try Sphinx though. In addition to high performance, it has done a lot of work to improve relevance. In the latest issue of Hacker magazine there is an interview with Andrey Aksenov (Sphinx developer), he talks about the basic principles by which he works.
With the help of Sphinx, you will seriously improve the quality of the issue, in relation to the way you want to solve the problem "on the forehead".