A method is provided for processing data in a database, wherein the database includes a first table and a second table. Each of the tables have a plurality of rows of data, wherein a key identifies one or more rows of data in the tables. There is a plurality of matching key pairs among the tables. Each key pair includes a key of a first table, and a matching key and a unique row of a second table. In operation, the method involves simultaneously processing row data of key pairs associated with a first row of the second table, and then simultaneously processing row data of key pairs associated with any remaining rows of the second table in sequential row order.