On 7/26/21 9:19 AM, Avi Weinberg wrote:
>
> Hi,
>
> I would like to populate the children_ids column with all the ids of
> the children recursively (+ grandchildren etc.)
>
> If I do it top-bottom I will end up doing extra work since there is no
> need to go all levels down if I can just compute my IMMEDIATE children
> "children_ids" and just concatenate all their lists.
>
> I looked at
> https://stackoverflow.com/questions/41376655/how-can-i-traverse-a-tree-bottom-up-to-calculate-a-weighted-average-of-node-va
> <https://stackoverflow.com/questions/41376655/how-can-i-traverse-a-tree-bottom-up-to-calculate-a-weighted-average-of-node-va>
>
> But was not able to get it to work on my case.
>
> Your assistance is most welcome!
>
> create table tree(id int primary key, parent int, children_ids text);
>
> insert into tree (id, parent) values
>
> (273, 0),
>
> (274, 273),
>
> (275, 273),
>
> (277, 273),
>
> (278, 277),
>
> (280, 275),
>
> (281, 280),
>
> (282, 281),
>
> (283, 282),
>
> (284, 282),
>
> (285, 282),
>
> (286, 282),
>
> (287, 282),
>
> (288, 282),
>
> (289, 282),
>
> (290, 281),
>
> (291, 290),
>
> (292, 290),
>
> (293, 290),
>
> (294, 290),
>
> (295, 290);
>
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I'm sorry, what output format are you looking for? Perhaps an array of
all descendants for each founder? (founder int, descendants int[]). I
recommend a null for no-known-parent rather than zero. Or just founder
int, descendant int? With or without sub-trees?