Question: Understanding the working of first() and last() functions (original) (raw)

ArcadeDB Version: ArcadeDB Server v23.3.1-SNAPSHOT (build 143b1a6/1677646375828/main)

JDK Version: JMX Metrics

OS: MacOS Ventura 13.2.1

Expected behavior

Instead of returning null, the first and last values of the multi-valued field (dataset_name/dataset_name_l) created in the subquery should be returned upon using the first() and last() functions respectively.

PS: I'm still learning about ArcadeDB referring to the official documentation. It's possible that I misunderstood something.

Actual behavior

Query 1: select name,first(dataset_name) from (select name,in('in_use').name as dataset_name from job)
Query 2: select name,first(dataset_name_l) from (select name,dataset_name.convert('list') as dataset_name_l from (select name,in('in_use').name as dataset_name from job))

There are a total of 7 job-type nodes and 15 dataset-type nodes. A job is attached to three dataset-type nodes in total (2 with 'in_use' and 1 with 'has_created' type edge). Please refer to the attached image for better visualization (image 1).

I want to check the working of the first() and last() functions. Both queries were created with the same intent. The subquery select name,in('in_use').name as dataset_name from job returns the expected result (image 2), however, while using the said functions to extract the first and last values, the result (images 3 & 4) comes out to be null with both queries.

Image 1:

Image 2:

Image 3:

Image 4:

Steps to reproduce

• There are two node types 'dataset' and 'job', with the string datatype property 'name' defined for both. The type 'dataset' contains 15 nodes, named from 'd1, d2,d3,...,d14', and type 'job' contains 7 nodes, named from 'j1,j2,...,j7'.
• I connected the database in the console and queried it to check the working of the FIRST() and LAST() functions.