Use of dynamic dictionary encoding with an associated hash table to support many-to-many joins and aggregations

Techniques are described herein for using a dynamic dictionary encoding with an associated hash table to support many-to-many join and aggregation operations. In an embodiment, within a first storage of a computing device, a first data structure that comprises a first dense grouping key column is created. The dense grouping key column includes a first plurality of dense grouping key values and one or more instances of a flag value. Within the first storage of the computing device, a second data structure is created that comprises a group-by column and a second dense grouping key column. The group-by column includes a plurality of group-by key values and the second dense grouping key column includes a second plurality of dense grouping key values. Within the first storage of the computing device, a third data structure, a hash table, is created that includes a hash bucket for each join key value that corresponds to an instance of the flag value. A result set for a query is determined using a combination of the first data structure, second data structure and/or the third data structure.