1. A sound data processing device for searching through a database, storing therein part performance data of a plurality of performance parts, each of the plurality of performance parts being associated with one performance part of a plurality of different performance parts of an ensemble, for particular part performance data, the part performance data for each of the performance parts including a sound generation pattern indicative of sound generation start timing of individual tones to be generated by the part performance data, said sound data processing device comprising: a processor configured to: acquire a first query pattern indicative of a first sound generation pattern to be made an object of search; search through the database for first part performance data including a second sound generation pattern matching the first query pattern; in response to a user's operation performed after searching through the database for the first part performance data including the second sound generation pattern matching the first query pattern: identify one of the first part performance data, whose second sound generation pattern is to be used as a second query pattern, from among searched-out part performance data from the database; and perform a second search for second part performance data matching a performance part associated with the identified one of the first part performance data from among the searched-out part performance data from the database and including a third sound generation pattern matching the second query pattern, using, as the second query pattern, the second sound generation pattern of the identified one of the first part performance data from among the searched-out part performance data from the database.