Scripts, streams, and CTEs - ChronusQL

Named streams are the contract

FROM names an input or an earlier CTE. INTO names an output. These identifiers bind the language to connections supplied by the host; they are not file paths embedded in SQL.

Input recordsJSON

{"ts":"2026-08-23T10:00:00Z","device":{"id":"A-17"},"reading":42.5}
{"ts":"2026-08-23T10:00:01Z","device":{"id":"A-17"},"reading":43.1}

Nested field projectionChronusQL

SELECT ts,
       device.id AS device_id,
       reading
INTO output
FROM input TIMESTAMP BY ts

Reuse work with WITH

A CTE is a named stream transformation. Later CTEs and output statements can consume it without repeating the definition.

Execution sketchOne input, shared logic, several outputs

FROMInput

WHEREClean CTE

reuseFast CTE

fan-outoutput_all

fan-outoutput_fast

CTEs form an acyclic flow. Final SELECT statements materialize only the outputs each consumer needs.

Filter once and fan outChronusQL

WITH Clean AS (
  SELECT ts, driver, speed
  FROM telemetry
  WHERE speed > 0
), Fast AS (
  SELECT ts, driver, speed
  FROM Clean TIMESTAMP BY ts
  WHERE speed > 300
)
SELECT * INTO output_all FROM Clean;
SELECT * INTO output_fast FROM Fast;

Script rules

Declare WITH definitions before final output statements.
Separate final output statements with semicolons.
A CTE can read a physical input or a previously declared CTE.
A script may write to multiple named outputs.
Field names projected by a CTE become the schema visible to downstream statements.