Something like this:

--CaseID: Comments: Userlogin

--1243546457 Great help UserA

--3123234353 AWESOME UserB

--2131314242 Support was terrible UserC

--2131314242 Support was terrible UserC

--2131314242 Support was terrible UserC

--2131314242 Support was terrible UserA

--3453453453 Could have been better UserB

declare @TestData table (

CaseID bigint,

Comments varchar(32),

UserLogin varchar(16)

);

insert into @TestData

values (1243546457, 'Great help', 'UserA'),

(3123234353, 'AWESOME', 'UserB'),

(2131314242, 'Support was terrible', 'UserC'),

(2131314242, 'Support was terrible', 'UserC'),

(2131314242, 'Support was terrible', 'UserC'),

(2131314242, 'Support was terrible', 'UserA'),

(3453453453, 'Could have been better', 'UserB');

with BaseData as (

select

CaseID,

Comments,

UserLogin,

rn = row_number() over (partition by CaseID, Comments, UserLogin order by UserLogin)

from

@TestData

)

select

CaseID,

Comments,

UserLogin

from

BaseData

where

rn = 1;