check if query builder already issued where or like?

I am so convenient using built-in codedigniter query builder.

I have to output searching to an existing page since that page involves multi-table.
Currently, I already have a lot of if there, I am curious how to check if statement db->where() or db->like() have been called or not.

I am already stuck here, and I am aware that the db->get() will erase the data filtering.
Any suggestion?