A multidimensional object, such as a language-integrated query (LINQ) object, can be generated based upon a grouping set operator and zero or more key selectors. The object can be utilized to query over a non-relational data source. The object can include a sequence of functions corresponding to each grouping related to the grouping set operator in order to provide multidimensional grouping representation. Furthermore, the object includes nested structures for optimized execution of the grouping set operator.