Choose SQL by the reader task ​

When evaluating Coordinator DB, start with the operations your application needs rather than inferring capabilities from a database category label. The public contract covers typed tables, constraints, transactions, joins, grouped aggregates and window functions.

A reporting task can be expressed directly:

SELECT account_id, count(*) AS event_count, sum(amount) AS total_amount
FROM events
WHERE day >= '2025-01-01' AND day < '2025-02-01'
GROUP BY account_id
ORDER BY total_amount DESC
LIMIT 20;

This example assumes the table contains the named columns. Define representative data and verify the result before measuring it. Use EXPLAIN QUERY PLAN to inspect access choices and query history to inspect the actual execution's duration and read work.

For a keyed application lookup, primary keys and targeted indexes may matter more than a wide grouped report. For a multi-step change, transaction scope and constraints matter. These are separate reader tasks, so a single benchmark or a storage label cannot stand in for validating them all.

Choose declared types for the actual value range and precision, and avoid projecting columns the caller does not need.

See SQL queries, indexes and query measurements.