A method, computer program and system for joining two tables, t₁ and t₂ are described. Each table contains rows and columns and is divided into one or more partitions. A correlation function is calculated between a first correlated value column of table t₁ and a second correlated value column of table t₂. Following a query request, a joining algorithm is used to join t₁ and t₂, using a reduced set of partitions based in part upon the correlation function.