1. A method for selecting a preferred data set, comprising: generating, by one or more processors, a candidate data set based on a first data set having a first join attribute and a first aggregate attribute, and a second data set having a second join attribute compatible with the first join attribute and a second aggregate attribute, wherein the candidate data set includes a total attribute having a value that is based on aggregating a value associated with the first aggregate attribute and a value associated with the second aggregate attribute; and selecting, by one or more processors, the preferred data set from the candidate data set based on the total attribute.