JavaScript Boolean Search Query Builder Interface Library?
http://redquerybuilder.appspot.com/ is not pretty but aiming to be usable by non-techy people.
I should make it clear that I'm one of the authors of this project.
I found this question on the Elastic Search forum, that is very similar to yours. An elastic search js client library is suggested : http://elasticsearch-users.115913.n3.nabble.com/javascript-query-builder-td1860558.html .
ExtJS has a Query Builder extension to their Grid control: http://www.developerextensions.com/index.php/extjs-grid-query-builder (look for the link above the table that says Query Builder).
I also found this, "Active Query Builder": http://aspquerybuilder.net/default.aspxThe feature list is : http://www.activequerybuilder.com/featurematrix.html?show=asp . It's an paid ASP.NET component that uses jQuery. It's pretty robust and may be more than you are looking for and also may or may not be compatible with your framework (you didn't specify), but it does look pretty cool.
Some more ASP.NET-based query builders are linked from : Web based visual query builder.
Here is web-service I came across recently: Advangle.
Looks like they use a kind of JavaScript library with UI similar to what you requested.