Abstract: Techniques described herein perform an index backbone join of data that is contained within two or more tables. Significantly, key data are selected from the indices constructed on the tables, and such data are filtered by the query-indicated criteria, before any data is selected from the tables themselves. Row identifiers of the rows remaining after the index filtering has been performed are then used to select the qualifying rows (only) from the tables. Data selected from the tables is joined to produce query results. Because all of the filtering is performed based on index entries prior to any table access, and because index access is typically much faster than table access, queries whose results require very large quantities of data from multiple tables can be performed much more quickly.