Query Language

A query is a Clojure map and can be written as plain EDN. Its main keys are :from, :to, :where, :derive, :select, :take, :drop, :order-by, and :group-by.

Predicate operators

Boolean expressions compose recursively: [:and expr ...], [:or expr ...], and [:not expr]. Date predicates include [:weekday? :monday], [:weekday-in #{:monday :friday}], [:month? 2], [:month-in #{1 2 12}], [:year? 2027], [:day-of-month? 1], [:day-between 1 15], [:iso-week? 1], [:quarter? 1], [:weekend?], [:leap-year?], [:month-start?], [:month-end?], [:year-start?], and [:year-end?].

Unknown operators, fields, malformed forms, and reversed bounds raise ex-info with a namespaced :type and useful path data. validate-query returns the date-coerced normalized query.

Use :group-by with an optional :aggregate vector. Supported aggregate operations are :count, :first-date, :last-date, :min-day, and :max-day. Without :aggregate, each key maps to a vector of matching projected records. :first-date and :last-date follow input order, so provide chronologically ordered input when that is the desired meaning.

Derived and selected fields

Built-in derived fields are :quarter, :month-length, :year-month, :iso-week, :iso-week-year, :days-from-start, and :month-index. A derive map explicitly names built-ins, for example {:quarter :quarter}. The last two require a query :from bound. Base fields include :date, :year, :month, :day, :weekday, :day-of-year, :year-month, :iso-week, :iso-week-year, :quarter, and boundary flags.

Selected fields are returned in a map with deterministic keyword ordering. Set :serializable? true to encode LocalDate and YearMonth values as ISO strings.

EDN input

read-query rejects tagged literals and uses clojure.edn/read-string. It never enables arbitrary reader functions. The library leaves transport-level size limits to the application so callers can apply a limit appropriate to their boundary.