Question

How can I insert to a table a value from “grouping” other table?
That means I have 2 table with different structure.

The table ORDRE with existed DATA

Table ORDRE:

ORDRE ID  |  CODE_DEST | 
-------------------------
    1     |     a      |    
    2     |     b      |    
    3     |     c      |    
    4     |     a      |    
    5     |     a      |    
    6     |     b      |    
    7     |     g      |    

I want to INSERT the value FROM Table ORDRE INTO TABLE VOIT:

 ID_VOIT  |  ORDRE ID  |    CODE_DEST | 
 ---------------------------------------
    1     |     1      |         a    |   
    1     |     4      |         a    |    
    1     |     5      |         a    |   
    2     |     2      |         b    |     
    2     |     6      |         b    |    
    3     |     3      |         c    |     
    4     |     7      |         g    |    

Answer 1

This is my best guess on what you need using only the info available.

declare @Ordre table
(
  ordre_id int,
  code_dest char(1)
)
declare @Voit table
(
  id_voit int,
  ordre_id int,
  code_dest char(1)
)

insert into @Ordre values
(1,'a'),
(2,'b'),
(3,'c'),
(4,'a'),
(5,'a'),
(6,'b'),
(7,'g')


insert into @Voit
select id_voit, ordre_id, rsOrdre.code_dest
from @Ordre rsOrdre
inner join
(
  select code_dest, ROW_NUMBER() over (order by code_dest) as id_voit
  from @Ordre
  group by code_dest
) rsVoit on rsVoit.code_dest = rsOrdre.code_dest
order by id_voit, ordre_id


select * from @Voit

Working Example.