SHOW PARTITIONS with order by in Amazon Athena

问题:

I have this query:

SHOW PARTITIONS tablename;

Result is:

dt=2018-01-12
dt=2018-01-20
dt=2018-05-21
dt=2018-04-07
dt=2018-01-03

This gives the list of partitions per table. The partition field for this table is dt which is a date column. I want to see the partitions ordered.

The documentation doesn't explain how to do it: https://docs.aws.amazon.com/athena/latest/ug/show-partitions.html

I tried to add order by:

SHOW PARTITIONS tablename order by dt;

But it gives:

AmazonAthena; Status Code: 400; Error Code: InvalidRequestException;

回答1:

I just faced the same issue and found a solution in information_schema database. If your table contains only one partitioning column, use the following query to get an ordered list:

SELECT partition_value
FROM information_schema.__internal_partitions__
WHERE table_schema = '<DB_NAME>'
        AND table_name = '<TABLE_NAME>'
ORDER BY partition_value

回答2:

From your comment it sounds like you're looking to sort the partitions as a way to figure out whether or not a specific partition exists. For this purpose I suggest you use the Glue API instead of querying Athena. Run aws glue get-partition help or check your preferred SDK's documentation for how it works.

There is also a variant to list all partitions of a table, run aws glue get-partitions help to read more about that. I don't think it returns the partitions in alphabetical order, but it has operators for filtering.

回答3:

The SHOW PARTITIONS command will not allow you to order the result, since this command does not produce a resultset to sort. This command only produces a string output.

You can on the other hand query the partition column and then order the result by value.

select distinct dt from tablename order by dt asc;