There is no language at this point, we always run an implicit
contains query on whatever you type, in all columns. We then suggest which columns have at least one cell that contains the string you typed, with sentences like "
whatever you typed in eligible column".
By contains I mean anywhere in the cell; for instance if you search for "book", it will find "facebook", "bookshelf" and "mybookstore.com".
This search field is like a global search, sort of like a Ctrl + F (or Cmd + F) in your browser. You don't need to know in advance in which column the data is. The flip side being that, indeed, you can't force it to search only within a particular column.
We will probably allow predicates in the future though, such as '>', '<' etc. for numerics, 'and' / 'or' conditions etc.