What is the regex that the boostrap datatable uses by default?

I would like to know which is the regex that the search box uses in the boostrap datatable, which is by default when we assign it to our table, since I would like to replicate it in a query that will obtain that same information from the table and export it in an Excel report, I know that the datatable contains buttons that do those actions, only that this time the printing of Excel would require more information than what is displayed in the datatable and an advanced customization.

So I want to replicate the search regex so that they can print the filtered results of the datatable, that replica would use it in SQL.