Joins returnerar inte korrekta resultat. Vad gör jag fel?

När du använder funktioner som antal, summa etc. måste du lägga till en grupp för sats för att styra grupperingen av resultaten:

select 
    concat(u.first_name, ' ', u.last_name) as name, 
    u.skill, 
    ut.name as team_name,
    (count(if(a.tech_id = u.user_id AND a.qc_id = 0 AND a.status = 2,1,0))) AS assigned_scopes,
    (count(if(a.tech_id = u.user_id  AND a.qc_id > 0 AND a.status = 3,1,0))) AS assigned_qa,
    (count(if(a.assignment_id=o.assignment_id and a.tech_id = u.user_id  AND a.status = 2 AND a.qc_id = 0 and o.class_id= 3,1,0))) AS assigned_canvass,
from am_ts_order o 
left join am_ts_assignment a
    ON a.assignment_id=o.assignment_id
left join am_user u
    ON a.tech_id=u.user_id
left join user_team ut
    ON u.user_team_id = ut.user_team_id
where u.user_role_id = 15
    and u.user_team_id = ut.user_team_id
order by u.first_name asc
group by a.tech_id

UPPDATERING:

Den här frågan ändrar IF-villkoren för att testa om en matchande rad hittades i några av de vänsteranslutna tabellerna:

select 
    concat(u.first_name, ' ', u.last_name) as name, 
    u.skill, 
    ut.name as team_name,
    count(if(
        (NOT a.tech_id IS NULL) AND 
        (NOT u.user_id IS NULL) AND 
        a.qc_id = 0 AND 
        a.status = 2,1,0)) AS assigned_scopes,
    count(if(
        (NOT a.tech_id IS NULL) AND 
        a.qc_id > 0 AND 
        a.status = 3,1,0)) AS assigned_qa,
    count(if(
        (NOT a.assignment_id IS NULL) AND
        a.assignment_id = o.assignment_id AND 
        a.tech_id = u.user_id AND 
        a.status = 2 AND 
        a.qc_id = 0 AND 
        o.class_id= 3,1,0)) AS assigned_canvass,
from am_ts_order o 
left join am_ts_assignment a
    ON a.assignment_id=o.assignment_id
left join am_user u
    ON a.tech_id=u.user_id
left join user_team ut
    ON u.user_team_id = ut.user_team_id
where u.user_role_id = 15
    and u.user_team_id = ut.user_team_id
order by u.first_name asc
group by a.tech_id