InfluxQL

InfluxQL is a SQL-like query language used to retrieve and analyze time-series data stored in InfluxDB. It was designed to provide familiar querying patterns for measurements, tags, and fields, with constructs tailored to time-based data such as automatic grouping by time intervals.

The syntax of InfluxQL centers on selecting data from a measurement, with optional filtering by time ranges and tag keys or values, and optional aggregation over time intervals. A representative query might look like: SELECT mean("usage") FROM "cpu_load" WHERE time > now() - 1h GROUP BY time(5m) FILL(null). Queries can also reference retention policies via the FROM clause, as in FROM "rp"."measurement". In addition to data queries, InfluxQL supports a set of administration and discovery commands such as SHOW DATABASES, SHOW MEASUREMENTS, SHOW TAG KEYS, and SHOW TAG VALUES.

Common features include: aggregations like MEAN, MAX, MIN, SUM, COUNT, and DERIVATIVE; time-based grouping with GROUP BY time(<interval>); filtering by tag keys and values; and options like FILL to specify how missing data within a time bucket should be treated. InfluxQL is optimized for high-volume time-series workloads and leverages InfluxDB’s data model, which organizes data into measurements, fields, and tags, plus retention policies to control data storage duration.

Limitations of InfluxQL include a lack of full SQL capabilities such as joins and complex subqueries in some contexts, and its evolution has been superseded in newer InfluxDB versions by Flux, a more expressive query language. InfluxQL remains supported for backward compatibility in many deployments, but Flux is recommended for new development efforts.