Grouping and Aggregates

A compact grouping and aggregates book for readers who need exact finite GROUP BY behavior: base rows, group buckets, COUNT rows, SUM integer values, aggregate output rows, HAVING-style keep/drop groups, empty inputs, and guarded expected group facts.

Grouping

Start With Base Rows
Make Group Buckets
Count Rows in Each Group
Sum Integer Values
Group Key Plus Aggregate
Keep or Drop Groups
No Hidden Groups
Honest by Construction