Abstract: In one aspect, a method may include receiving a query associated with a plurality of data sources, wherein the query includes a first attribute; identifying that a query operator, which is associated with execution of the query and the first attribute, includes a first input from a first data source of the plurality of data sources and a second input from a second data source of the plurality of data sources; determining that the first attribute at the second data source corresponds to null; pruning, based on the determined null, the second input from the second data source to inhibit a select from the second data source; and in response to the pruning, performing the query operator by selecting, from the first data source, a column corresponding to the first attribute. Related systems, methods, and articles or manufacture are also disclosed.