Nested set INSERT operation for SQLite

I am trying to implement the nested-set model for a sqlite database. So far I have implemented getting leaf nodes, finding subordinates etc. I am using this tutorial as a reference However, I am stuck at inserting a new node. Here's the code from the site

LOCK TABLE nested_category WRITE;

SELECT @myRight := rgt FROM nested_category
WHERE name = 'TELEVISIONS';

UPDATE nested_category SET rgt = rgt + 2 WHERE rgt > @myRight;
UPDATE nested_category SET lft = lft + 2 WHERE lft >开发者_运维知识库 @myRight;

INSERT INTO nested_category(name, lft, rgt) VALUES('GAME CONSOLES', @myRight + 1, @myRight + 2);

UNLOCK TABLES;

I know that there's no lock table in sqlite.. my problem here is that I need to pass the result of the first query to the next one. Here it's done by using a user-created variable by @. I couldn't figure out how to do it in SQLite.

Thanks in advance.

An ideea is to replace the variable myRight with the query that generated it. That is to move the code into pure SQL.

UPDATE nested_category SET rgt = rgt + 2 
WHERE rgt > (SELECT rgt 
             FROM nested_category
             WHERE name = 'TELEVISIONS');

UPDATE nested_category SET lft = lft + 2 
WHERE lft > (SELECT rgt 
             FROM nested_category
             WHERE name = 'TELEVISIONS');

INSERT INTO nested_category(name, lft, rgt)
SELECT 'GAME CONSOLES', rgt + 1, rgt + 2 
FROM nested_category
WHERE name = 'TELEVISIONS' ;