Varying Calculations for Rows in SQLite

Question

My SQL table is set out as such:

• Key (primary key)
• Parent key (many primary keys to a parent key)
• Points 1
• Points 2
• Modifier

The modifier determines the effect on total points. I.e.

• Modifier A - total points = (points 1 + points 2)*0.1
• Modifier B - total points = (points 1 + points 2)*0.2
• Modifier C - total points = (points 1 + points 2)*0.7

Ideally I'd like to produce a table of:

• Parent key
• Total modified points for that key (e.g. 100 * 0.2 + 150 * 0.5 + 180 * 0.7)

I cannot get it to work for the life of me. The closest I've come is in the code below, which outputs a row for each parent key and a column for each modifier. However, each column is filled with a single value despite these statements all producing the values I want in isolation.

SELECT table.parent, t1.one, t1.two, t1.three
FROM
table
LEFT JOIN

(SELECT 
(SELECT ((sum(points1)+sum(points2))*0.1) FROM table WHERE (modifier = "modifier one") GROUP BY key) as 'one', 
(SELECT ((sum(points1)+sum(points2))*0.2) FROM table WHERE (modifier = "modifier two") GROUP BY key) as 'two',
(SELECT ((sum(points1)+sum(points2))*0.7) FROM table WHERE (modifier = "modifier three") GROUP BY key) as 'three'
) t1

GROUP BY table.parent