The present invention concerns methods and apparatus for incorporating parenthetical expression capability in an interactive tabular query interface, wherein the interactive tabular query interface can be used to search computer resources like computer databases. The methods and apparatus of the present invention permit a user through the medium of a parenthetical-expression-capable tabular query interface both to group at least two logical expressions with a single level of parentheses and to embed parenthetical expressions within multi-level parenthetical expressions. The methods and apparatus of the present invention also permit a user to quickly and easily logically un-combine expressions that have been grouped using a parenthetical expression feature of a tabular query user interface made in accordance with the present invention. Further, the interactive tabular query interface also has a preview window for depicting dynamically a query as it is formulated.