Real-Time Analytics Query Language
The Real-Time Analytics Query Language (RAQL) is an easy-to-learn, SQL-like language to query and analyze large, streaming datasets. Users access datasets in mashups using EMML extension statements that leverage RAQL.
RAQL gives you direct, streaming access to data:
In files, without registering them as
Presto mashables.
In databases or from URL-addressable services.
In any number of snapshots for
Presto mashables or mashups.
Stored in the
Presto Analytics In-Memory Stores.
Extension statements in EMML also let you store large datasets or query results in the Presto Analytics In-Memory Stores.
You can also use RAQL with results for any Presto mashable or mashup.
RAQL works with data in CSV, XML or JDBC result formats. Data should be in a flat hierarchy, with simple columns and rows. RAQL queries can:
Filter dataset columns and rows using simple or complex criteria.
Sort data with any number of levels.
Group data in groups, partitions or windows and analytic functions to these sets.
Use subqueries and many other common SQL features to handle complex requirements.
Use the plain and analytic functions that are built into
Presto plus any extensions that user define.
RAQL Extensions: User-Defined Functions
In addition to the RAQL functions built into Presto, you can define additional functions to use in RAQL queries to handle unique or domain-specific needs. User-defined functions can be plain functions. Or they can be aggregate or window analytic functions that use the Presto RAQL User-Defined Function API.
You add user-defined functions in libraries with library names that you assign. This allows you to manage functions and ensure that function names are unique.
