1. A method comprising: storing a query that aggregates data from at least one database object; for a set of one or more columns on which the aggregated data is grouped, before evaluating the query to aggregate the data, creating: different storage containers for each different set of one or more values that occurs in the set of one or more columns without creating storage containers for one or more sets of one or more values that do not occur in the set of one or more columns; evaluating the query to aggregate the data from the at least one database object at least in part by using keys from the at least one database object to locate corresponding storage containers of the different storage containers; wherein the method is performed by one or more computing devices.