在查询 postgres 中访问数组元素

Question

I'm currently building a query to retrieve some data from my db, I need to access the documents stored in an array, this is how the table crm_company looks:

+ company_id +         documents_avaiable       + 
-     1      - [71788176,98705180,21468287,...] -   
-     2      - [11218494,12825726,10353038,...] -                                 

I have another table for users by document crm_user which looks like this:

+ user_document +     email     +
-   71788176    - abc@email.com -  
-   98705180    - def@email.com - 
-   11218494    - hef@email.com - 

What I want as a final result is:

+ user_document +     email     + company +
-   71788176    - abc@email.com -    1    -
-   98705180    - def@email.com -    1    -

I just have tried somehing like the following:

select documents_avaiable[0] from crm_company where crm_company.id = 1

But I'm still unable to retrieve the documents from array.

Thanks in advance for any hint or help.

Answer 1

If it's too late to follow the advice in the comment of Laurenz Albe then do this:

1. Use a query (or create a view) to have the list of company documents normalized

   create view company_documents as select t.company_id, l.document_id from crm_company t cross join lateral ( select unnest(t.documents_avaiable) as document_id ) l;

2. Access documents' details in other tables by document_id using join

   select cd.document_id user_document, cd.company_id company, d.email from company_documents cd join crm_user d on cd.document_id = d.user_document;