Find average of odd numbers

Question

Hi All,
Please I have the below table structure

With values like below

The record count at any time will always be in multiple of 3 that is 3 or 6 or 9 or 12 or 15 or 18 or 21 etc.
Please can I get a query that can find the average weight of every 3 records with equivalent row number like below

Answer 1

Hi @Michael M.M. D'Angelo ,

You can try the following. Thanks!

DECLARE @test TABLE (ID INT IDENTITY, Weight decimal(18, 5));  
  
insert into @test values('10');  
insert into @test values('10');  
insert into @test values('10');  
insert into @test values('11');  
insert into @test values('11');  
insert into @test values('11')  
insert into @test values('12')  
insert into @test values('12')  
insert into @test values('12')  
insert into @test values('13')  
insert into @test values('13')  
insert into @test values('13')  
insert into @test values('14')  
insert into @test values('14')  
insert into @test values('14')  
  
select SN, avg(Weight) as AverageWeight from  
(select *, (id+2)/3 as SN  from @test) as t   
group by SN  

Answer 2

Check a query:

;
with Q as ( select *, ntile(3) over (order by ID) as SN from Table)
select SN, avg(Weight) as AverageWeight from Q group by SN

If it does not work, then show how to divide the numbers into three groups.