Adaptive Server provides four primary join strategies: NestedLoopJoin, MergeJoin, HashJoin, and NaryNestedJoin, which is a variant of NestedLoopJoin. In versions earlier than 15.0, NestedLoopJoin was the primary join strategy. MergeJoin was also available, but was, by default, not enabled.
Each join operator is described in further detail below. A general description of the each algorithm is provided. These descriptions give a high-level overview of the processing required for each join strategy.
