I hope this is not a duplicate, I red some posts, but could not figure out how to fix this.
I have a table like this
CREATE TABLE yo (ad INTEGER PRIMARY KEY, pa INTEGER, pd INTEGER);
INSERT INTO yo VALUES
(1,1,1),(2,1,3),(3,1,4),(4,3,5),(5,4,2),(6,3,8),(7,1,9),(8,6,7),(9,3,6);
.header on
.mode column yo
select * from yo;
ad pa pd
---------- ---------- ----------
1 1 1
2 1 3
3 1 4
4 3 5
5 4 2
6 3 8
7 1 9
8 6 7
9 3 6
I can create a temp table using CTE to obtain the depth level of col 'pd' like this
CREATE table ui AS
WITH RECURSIVE ui(a,l) AS
( VALUES(1,0)
UNION ALL
SELECT yo.ad, ui.l+1
FROM yo JOIN ui ON yo.pa=ui.a
WHERE yo.pa!=yo.ad
ORDER BY 2 desc
)
SELECT a,l FROM ui;
select * from ui;
a l
---------- ----------
1 0
2 1
3 1
4 2
5 3
6 2
8 3
9 2
7 1
Then I want to ADD a col to table 'yo' and enter th ui.l in there
ALTER TABLE yo ADD COLUMN lv INTEGER;
UPDATE yo SET lv=
(SELECT ui.l
FROM ui
WHERE ui.a=yo.ad);
select * from yo;
ad pa pd lv
---------- ---------- ---------- ----------
1 1 1 0
2 1 3 1
3 1 4 1
4 3 5 2
5 4 2 3
6 3 8 2
7 1 9 1
8 6 7 3
9 3 6 2
All works fine. Now I like to combine the temp table 'ui' create and table 'yo' update in 1 request?
I tried many many combanation bout could not find a solution, I sure this is obvious, but I am not fluent enough to get it.
Should the CTE creation be before the UPDATE like in
How to use CTE's with update/delete on SQLite?
Or should the CTE be computed into a select inside the UPDATE
Thanx in advance for any helps
Cheers, Phi