Module aggregate 

GROUP BY and aggregate planning.

Functions

convert_group_by

Convert GROUP BY clause to SqlExpr list.

extract_aggregates_from_projection

Extract aggregate expressions from SELECT projection.

group_by_output_aliases

Derive the SELECT-list output alias for each GROUP BY key by correlating each key with the projection item that references the same column. Returns a Vec parallel to group_by: Some(alias) when a projection item explicitly aliases that grouped column (SELECT k AS label ... GROUP BY k), otherwise None (the output column name falls back to the raw grouped column name).

plan_aggregate

Plan an aggregate query (GROUP BY + aggregate functions).