Re: Return product category with hierarchical info

I’m also no expert, it’s been a decade or so since I do not use psql
But maybe

Select level3.id, level3.name, level2.name, level1.name,
From category level3
Join category level2
On level2.Id = level3.parent
Join category level1
On level1.Id = level2.parent

Best,
Oliver

Sent from Oliver’s iPhone

> On 5 Jan 2022, at 12:19, Richard Klingler <richard(at)klingler(dot)net> wrote:
>
> Good afternoon (o;
>
>
> First of all, am I am totally no expert in using PGSQL but use it mainly for simple web applications...
>
>
> Now I have a table which represents the categories for products in a hierarchical manner:
>
> id | name | parent
>
>
> So a top category is represented with parent being 0:
>
> 1 | 'Living' | 0
>
>
> The next level would look:
>
> 2 | 'Decoration' | 1
>
>
> And the last level (only 3 levels):
>
> 3 | 'Table' | 2
>
>
> So far I'm using this query to get all 3rd level categories as I use the output for datatables editor as a product can only belong to the lowest category:
>
> select id, name from category
> where parent in (select id from category where parent in (select id from category where parent = 0))
>
> But this has a problem as more than one 3rd level category can have the same name, therefore difficult to distinguish in the datatables editor which one is right.
>
>
> So now my question (finally ;o):
>
>
> Is there a simple query that would return all 3rd levels category ids and names together with the concatenated names of the upper levels? Something like:
>
>
> 3 | 'Table' | 'Living - Decoration'
>
>
> thanks in advance
>
> richard
>
>
>
> PS: If someone could recommend a good ebook or online resource for such stupid questions, even better (o;
>
>
>
>