Finding customers with identical orders

Question

I need to find customers who have made identical orders. (Using T-SQL)

Order

OrderID Customerer  
1   2   
2   5   
3   6            


        

Answer 1

Here's the most simple approach.

-- sample table
create table x
    (
         LineId int identity(1, 1)
        ,InvoiceFk int
        ,ProductFk int
        ,Quantity int
    )

-- sample data
insert into x 
(InvoiceFk, ProductFk, Quantity) values
     (11, 1, 1)
    ,(11, 2, 1)
    ,(11, 3, 1)
    ,(12, 1, 2)
    ,(12, 2, 2)
    ,(12, 3, 2)
    ,(13, 1, 3)
    ,(13, 2, 3)
    ,(13, 3, 3)

-- your order, probably from a parameter
declare @order table
    (
         InvoiceFk int
        ,ProductFk int
        ,Quantity int
    )
insert into @order
(InvoiceFk, ProductFk, Quantity) values
     (14, 1, 1) -- duplicate invoice 11
    ,(14, 2, 1)
    ,(14, 3, 1)

-- your order unique checksum
declare @orderCheck int
select @orderCheck = checksum_agg(checksum(ProductFk, Quantity))
from @order

-- test your order in existing data
declare @match int
select @match = 
    (
        select TOP 1 InvoiceFk from
        (
            select
                 InvoiceFk
                ,checksum_agg(Col1) as Col2
            from
                (
                select 
                     InvoiceFk
                    ,checksum(productfk, quantity) as Col1
                from x
                ) as T1
            group by
                InvoiceFk
        ) as T2
        where 
            T2.Col2 = @orderCheck
    )


-- evaluate if your order is unique or not
if (@match is not null)
begin
    print 'Identical to invoice: ' + Str(@match);
end
else
begin
    print 'Order is unique';
end

-- clean up sample table
drop table x    

Best of luck!