Method, system, and program for determining the join ordering of tables in a join query

摘要

Disclosed is a system, method, and program for joining a multi-column table and at least two satellite tables. Each satellite table is comprised of multiple rows and at least one join column and each multi-column table is comprised of multiple rows and join columns corresponding to the join columns in the satellite tables. A query including predicates is received. A join predicate column comprises the satellite table and multi-column table join column to which at least one query predicate applies. A determination is then made as to whether there is at least one index on the multi-column table including at least one column for one join predicate column. One index is selected. The ordering of the join predicate columns in the selected index is used to determine the join order of the satellite tables and the multi-column table. The satellite tables and multi-column tables are then joined in the determined join order.