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 Structured Query Language (SQL) (pronounced ''S-Q-L''; or alternatively as "sequel") is a domain-specific language used to manage data, especially in a relational database management system (RDBMS). It is particularly useful in handling s ...

query language A query language, also known as data query language or database query language (DQL), is a computer language used to make queries in databases and information systems. In database systems, query languages rely on strict theory to retrieve informa ...

adapted for accessing the astronomical datasets of the virtual observatory, via the Table access protocol (TAP). ADQL is designed to handle large datasets distributed over several locations, while not retrieving data that is not needed.

Language

ADQL is a

that allows data to be retrieved via a single command, the ''select'' statement, which is designed to perform as the ''select'' statement in the

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

* * * * * * Query languages {{Astronomy-stub