Open queries are queries, where the result will show how each respondent replied. The result will not show any count of how many responded in which ways, it will just list the names of the people who responded with each choice.
Example of the result of a simple open query:
Open and Closed Forums
You can place a query in either an open, a closed or a restricted forum. A query in an open forum is accessible to anyone, while a query in a closed forum is only accessible to the members of the closed forum. A query in a restricted forum is accessible to all members of its category/user group. Thus note that an Open Query and an Open Forum are two quite different things.
A secret ballot is a query, where the information about who replied what is not shown. Even if the computer has stored who replied what, this is never shown to any user. The respondent is thus anonymous.
Example of the result of a simple secret ballot:
Note that if you put a secret ballot into a forum, to which people can go without logging in, then you will not have any security against multiple replies by the same person. With open queries, the list of who replied what gives some security against such misuse.