Technologies are generally described for methods and systems to join a first source dataset with a second source dataset. In an example, a processor may receive a request to join the first and second source datasets based on a condition. The processor may determine a first range of attribute values from the first source dataset, and a second range of attribute values from the second source dataset. The processor may produce a filtered dataset based on a comparison of the first and second ranges. A map unit may transform the filtered dataset and the second source dataset into first and second mapped datasets based on the condition. A reduce unit may transform the first and second mapped datasets into first and second reduced datasets based on the condition. A combiner unit may combine the first and second reduced datasets to join the first and second source datasets.