A system and method of querying hybrid multi data sources includes receiving a query at a hybrid multi data source running on a computer server, creating a list of data sources, filtering the list of data sources based on data source hints included in the query, filtering the list of data sources based on data source rules, forming one or more query plans for processing the query, evaluating each of the query plans, selecting a first query plan from the query plans based on results of the evaluating, and performing the first query plan. Each query plan corresponds to a data source in the filtered list of data sources. In some examples, the first query plan has a lowest cost of each of the query plans. In some examples, the first query plan is based on probabilities associated with the cost of each of the query plans.