Astronomical Data Query Language (ADQL) is a language for astronomical data query based on SQL 92.
Overview
ADQL is a specialized variant of the
SQL query language
Query languages, data query languages or database query languages (DQL) are computer languages used to make queries in databases and information systems. A well known example is the Structured Query Language (SQL).
Types
Broadly, query language ...
adapted for accessing the astronomical datasets of the
virtual observatory, via the Table access protocol (TAP). ADQL is dedigned to handle large datasets distributed over several locations, while not retrieving data that is not needed.
Language
ADQL is a
query language
Query languages, data query languages or database query languages (DQL) are computer languages used to make queries in databases and information systems. A well known example is the Structured Query Language (SQL).
Types
Broadly, 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
References
Footnotes
Sources
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Query languages
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