Module select 

Structs

AggregateCall

A parsed aggregate call like COUNT(*), SUM(salary), COUNT(DISTINCT dept).

OrderByClause

A parsed ORDER BY clause: a single sort key (expression), ascending by default. Phase 7b widened this from “bare column name” to “arbitrary expression” so KNN queries of the form ORDER BY vec_distance_l2(col, [...]) LIMIT k work end-to-end. The expression is evaluated per-row at execution time via eval_expr; the simple ORDER BY col form still works because that’s just an Expr::Identifier taking the same path.

ProjectionItem

One entry in the projection list.

SelectQuery

A parsed, simplified SELECT query.

Enums

AggregateArg

What the aggregate is fed: * (only valid for COUNT) or a bare column.

AggregateFn

Aggregate function name. v1 covers the SQLite-classic five.

Projection

What columns to project from a SELECT.

ProjectionKind

What an individual projection item produces.