SQL : SELECT SUM WHERE CONDITION - mysql

Question

I've got some troubles about SQL request :
I have a table like this table data image
I would like to create a view from this table to get :
Time_A : SUM of a column (total_time_taken) WHERE column (is_radiant)=1
Time_B : SUM of the same column (total_time_taken) WHERE column (is_radiant)=0
Time_AB : SUM of the column (total_time_taken) WHERE column (is_radiant)=0 OR (is_radiant)=1
SELECT
SUM(`matchpickban_radiant`.`total_time_taken`) AS `draft_time_radiant`,
SUM(`matchpickban_dire`.`total_time_taken`) AS `draft_time_radiant`
FROM
(`matchpickban` AS `matchpickban_radiant`
JOIN `matchpickban` AS `matchpickban_dire` ON ((`matchpickban_dire`.`idmatchpickban` = `matchpickban_radiant`.`idmatchpickban`)))
WHERE
`matchpickban_radiant`.`is_radiant` = 1
AND `matchpickban_dire`.`is_radiant` = 0
Actually I can run this request without syntax error but the result is NULL cause no data can be equal to 0 AND equal to 1 in the same time, obviously...
Also, I don't know if it's possible to make a JOIN the table to itself as I did (matchpickban JOIN matchpickban).
If syntax is correct I need to place my WHERE CONDITION away but don't know how, is it possible to replace it with 2 IF statement (IF is_radiant=0 SUM(...))
Thx for reading and helping me about this issue I got !
If you need more info about table or request I will give you all you need !

Answer 1

No need for a self-join or complex logic, you can just use conditional aggregation, which consists in using conditional expression within aggregate functions.
In MySQL, you could go:
select
sum(is_radiant * total_time_taken) time_a,
sum((1 - is_radiant) * total_time_taken) time_b,
sum(total_time_taken) time_ab
from matchpickban
where is_radiant in (0, 1)
This works because is_radiant is made of 0/1 values only - so this simplifies the logic. A more canonical way to phrase the conditional sums would be:
sum(case when is_radiant = 1 then total_time_taken else 0 end) time_a,
sum(case when is_radiant = 0 then total_time_taken else 0 end) time_b,