Module join 

Physical relational join operators.

Structs

HashJoin

Equality join backed by a canonical SQL-key hash table. SQL NULL keys never match. An optional residual predicate is evaluated on hash candidates before either side is marked matched, preserving mixed equijoin/non-equality ON semantics for every outer-join shape.

NestedLoopJoin

Nested-loop implementation for arbitrary join predicates and every SQL outer-join shape. Predicate evaluation happens against the merged row, so qualified columns and engine-provided scalar/subquery semantics remain available through the shared expression evaluator.