Astronomical Data Query Language

Astronomical Data Query Language is a language for astronomical data query based on SQL 92.

Overview

ADQL is a specialized variant of the SQL query language adapted for accessing the astronomical datasets of the virtual observatory, via the Table access protocol. ADQL is designed to handle large datasets distributed over several locations, while not retrieving data that is not needed.

Language

ADQL is a query language that allows data to be retrieved via a single command, the select statement, which is designed to perform as the select statement in the SQL language. ADQL has extensions designed to improve handling of astronomical data such as spherical co-ordinates that are not handled by standard SQL.

Implementations

ADQL is implemented in packages such as TOPCAT.

Example

SELECT source_id, ra, dec
FROM gaiadr1.tgas_source
WHERE phot_g_mean_flux > 13