Insert into #tblHeader
SELECT * FROM myFunc


select * 
from
#tblHeader left join
(
SELECT id, field, id2
FROM 
(SELECT tblDetail1.id, tblDetail1.field, #tblHeader.id2
FROM
#tblHeader inner join tblDetail1 on #tblHeader.id = tblDetail1.id
Group by tblDetail1.id, tblDetail1.field, #tblHeader.id2
 
union all
SELECT tblDetail2.id, tblDetail2.field, #tblHeader.id2
FROM
#tblHeader inner join tblDetail2 on #tblHeader.id =tblDetail2.id
Group by tblDetail2.id, tblDetail2.field, #tblHeader.id2
) AS q1
GRUP by  id, field, id2) as q2
On #tblHeader.id2 = q2.id2 

Insert into #tblHeader
SELECT * FROM myFunc


select #tblHeader.fielNew1, #tblHeader.fielNew2,  q2.id, q2.id2,  q2.field, q2.qnt1,  q2.qnt2,  (Case When ISNUll(q2.id2,0)=0 then 0 else q2.qnt2 - q2.qnt1) as qnt3
from

#tblHeader left join
(
SELECT id, field, id2, Sum(qnt1) as qnt1,  Sum(qnt2) as qnt2
FROM 

(
SELECT tblDetail1.id, #tblHeader.id2, tblDetail1.field,  tblDetail1.qnt as qnt1, 0 as qnt2
FROM
#tblHeader inner join tblDetail1 on #tblHeader.id = tblDetail1.id 

union all

SELECT #tblHeader.id, tblDetail2.id2,  tblDetail2.field, 0 as qnt1, tblDetail2.qnt as qnt2
FROM
#tblHeader inner join tblDetail2 on #tblHeader.2id =tblDetail2.2id
) AS q1

GROUP BY  id,  id2, field
) as q2

On #tblHeader.id = q2.id

select fielNew1, fielNew2id, id2, field
,SUM(isnull(d1.qnt,0)) as qnt1
,SUM(isnull(d1.qnt,0)) as qnt2
,SUM(case when id2 is null then 0 else isnull(d2.qnt,0) - isnull(d1.qnt,0) end as qnt3
from #tblHeader h
left join tblDetail1 d1 on h.id  = d1.id 
left join tblDetail2 d2 on h.id2 = d2.id 
group by fielNew1, fielNew2, id, id2, field