adjacency-list

I've spent the last few hours trying to find the solution to this question online. I've found plenty of examples on how to convert from nested set to adjacency... but few that go the other way around. The examples I have found either don't work or use MySQL procedures. Unfortunately, I can't use procedures for this project. I need a pure PHP solution. I have a table that uses the adjacency model below: id parent_id category 1 0 Books 2 0 CD's 3 0 Magazines 4 1 Books/Hardcover 5 1 Books/Large Format 6 3 Magazines/Vintage And I would like to convert it to a Nested Set table below: id left right

I have an organization table that has an id , a parent_id , and a name column. There are roughly 50k rows in this table. There is just one top level parent and the rest are all under that. In Oracle, I am able to easily retrieve the current depth of a particular organization with the level pseudocolumn: SELECT id, parent_id, level, name FROM organizations START WITH parent_id = 1 CONNECT BY PRIOR id = parent_id I am at a loss of what the proper way to do the above in MySQL is. I need to fetch the entire tree along with the node's depth in one query. There are a plethora of questions on

Hello I understand the concepts of adjacency list and matrix but I am confused as to how to implement them in Python: An algorithm to achieve the following two examples achieve but without knowing the input from the start as they hard code it in their examples: For adjacency list: a, b, c, d, e, f, g, h = range(8) N = [ {b:2, c:1, d:3, e:9, f:4}, # a {c:4, e:3}, # b {d:8}, # c {e:7}, # d {f:5}, # e {c:2, g:2, h:2}, # f {f:1, h:6}, # g {f:9, g:8} # h ] For adjacency matrix: a, b, c, d, e, f, g, h = range(8) _ = float('inf') # a b c d e f g h W = [[0,2,1,3,9,4,_,_], # a [_,0,4,_,3,_,_,_], # b [_

in my MySQL schema, I have the category(id, parentid, name) table In the MSSQL, I have that CTE query (to build a category tree from the bottom up for a supplied category ID: with CTE (id, pid, name) as ( select id, parentid as pid,name from category where id = 197 union all select CTE.pid as id , category.parentid as pid, category.name from CTE inner join category on category.id = CTE.pid ) select * from CTE How to 'transform' that query to MySQL ? Jon Black Unfortunately MySQL doesn't support CTE (Common Table Expressions). This is long overdue IMO. Often, you can just use a subquery instead