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olapsnappydata

Where do I learn more about the SnappyData Column OLAP syntax?

I'm new to OLAP and SnappyData. My question is very specific. I want to know where to read further documentation on the SnappyData 'column' query language for OLAP queries. Perhaps it is an industry standard. Perhaps it is SnappyData specific. I don't know.

For clarification, I'm looking at the QuickStart scripts and trying to make sense of the column tables, AIRLINE and the queries in olap_queries.sql. For example, given this query:

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---- Which Airlines Arrive On Schedule? JOIN with reference table ----
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select AVG(ArrDelay) arrivalDelay, description AirlineName, UniqueCarrier carrier 
  from airline, airlineref
  where airline.UniqueCarrier = airlineref.Code 
  group by UniqueCarrier, description 
  order by arrivalDelay;

I want to understand the constructs like 'description AirlineName,' . How does the syntax dictate that description is from the join on airlineref? Please, somebody, point me to where I can learn about this syntax.

Solution

  • The description AirlineName is standard column alias specification (where AS is optional) where first one must unambiguously resolve to a table column name in one of the join tables while second one is the alias.

    The syntax is the same as Spark SQL syntax. Unfortunately documentation is sparse for it like here or here but it is core SQL-92 compliant for select queries.