如何在 ArangoDB 过滤中使用数组值？

Question

stack overflow community i am relatively new for arango and wants to build an AQL query using two collection please help me

first collection:- user JSON:- "user_id": "abcd", "program_info": [ { "program_id": 101, } ]

Second collection:- program JSON:- { "program_id":101, "program_name": "test" }

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i am building query to get info of program name using both collection if user_id will supplied FOR u IN user FILTER u.user_id =="abcd" FOR p IN program FILTER p.program_id == u.program_info[*].program_id RETURN p.program_name

but i am getting blank [] array please help me

Answer 1

The expression u.program_info[*].program_id returns an array with all program_id attributes from the objects in the program_info array. However, you are comparing this array with the scalar value p.program_id which does match and therefore you get an empty array. I suppose you want to check if p.program_id is contained in user's program_info . That could be done like this:

FOR u IN user
  FILTER u.user_id =="abcd"
  FOR p IN program
    FILTER p.program_id IN u.program_info[*].program_id
    RETURN p.program_name

However, for better index usability it might even be better to rewrite your query like this (provided you have an index on program_id for the program collection):

FOR u IN user
  FILTER u.user_id =="abcd"
  FOR pid IN u.program_info[*].program_id
    FOR p in program
      FILTER p.program_id == pid
      RETURN p.program_name