Is there a way to remove repetitve data from output in a single column

September 30, 2022

Is there a way blank out the repetitive customer ids, and just leave the first ones for each customer?

declare @orderTable table (
customerid int,
orderAmt decimal(18,4)
)

insert @orderTable
values
(1,10),
(1,20),
(1,20),
(1,20),
(3,10),
(3,15),
(3,30),
(3,10)

select * from @orderTable
order by customerid

Expected outpu:

customerid  orderAmt
1   10.0000
    20.0000
    20.0000
    20.0000
3   10.0000
    15.0000
    30.0000
    10.0000

>Solution :

Really belongs in the presentation layer. That said, you would also need a proper sequence to maintain an explicit order.

You may want to replace ... order by (Select null) ... with ... order by SomeCol ...

select customerid = case when row_number() over (partition by Customerid order by (Select null)) = 1 then customerid end 
      ,orderAmt
 From  @orderTable O
 order by O.customerid

Results

EDIT – If You DON’T WANT NULL

select customerid = concat('',case when row_number() over (partition by Customerid order by (Select null)) = 1 then customerid end)
      ,orderAmt
 From  @orderTable O