declare @next_id bigint
--/Получаем максимальное значение identity среди всего набора таблиц и сдвигаем вправо на 1млн
select @next_id = MAX(last_id)+1000000 from 
(
 select IDENT_CURRENT('[ID_0].[dbo].[Posts]')				last_id
 union
 select IDENT_CURRENT('ID_1].[dbo].[Posts]')	 
 union
 select IDENT_CURRENT('[ID_2].[dbo].[Posts]')	
  union
 select IDENT_CURRENT('[ID_3].[dbo].[Posts]')	 
  union
 select IDENT_CURRENT('[ID_4].[dbo].[Posts]')	 
  union
 select IDENT_CURRENT('[ID_5].[dbo].[Posts]')	 
  union
 select IDENT_CURRENT('[ID_6].[dbo].[Posts]')	 
  union
 select IDENT_CURRENT('[ID_7].[dbo].[Posts]')	 
  union
 select IDENT_CURRENT('[ID_8].[dbo].[Posts]')	 
  union
 select IDENT_CURRENT('[ID_9].[dbo].[Posts]')	 
)T
set @next_id = ROUND(@next_id, -1) --/Округляем до 0 полученное максимальное значение identity
select @next_id

use ID_0
select @next_id
--DBCC CHECKIDENT ('dbo.Posts', RESEED, @next_id);  --/Присваиваем новое значение identity нулевой таблице

use ID_1
set @next_id = @next_id+1  --/Сдвигаем на 1 значение identity учитывая кратность
select @next_id
--DBCC CHECKIDENT ('dbo.Posts', RESEED, @next_id);  

use ID_2
set @next_id = @next_id+1
select @next_id
--DBCC CHECKIDENT ('dbo.Posts', RESEED, @next_id);  

use ID_3
set @next_id = @next_id+1
select @next_id
--DBCC CHECKIDENT ('dbo.Posts', RESEED, @next_id);  

use ID_4
set @next_id = @next_id+1
select @next_id
--DBCC CHECKIDENT ('dbo.Posts', RESEED, @next_id);  

use ID_5
set @next_id = @next_id+1
select @next_id
--DBCC CHECKIDENT ('dbo.Posts', RESEED, @next_id);  

use ID_6
set @next_id = @next_id+1
select @next_id
--DBCC CHECKIDENT ('dbo.Posts', RESEED, @next_id);

use ID_7
set @next_id = @next_id+1
select @next_id
--DBCC CHECKIDENT ('dbo.Posts', RESEED, @next_id); 

use ID_8
set @next_id = @next_id+1
select @next_id
--DBCC CHECKIDENT ('dbo.Posts', RESEED, @next_id);  

use ID_9
set @next_id = @next_id+1
select @next_id
--DBCC CHECKIDENT ('dbo.Posts', RESEED, @next_id);