SQL Server 2008: TOP 10 and distinct together

Question

As the title says, I'm using SQL Server 2008. Apologies if this question is very basic. I've only been using SQL for a few days. Right now I have the following query:

SELECT TOP 10 p.id, pl.nm, pl.val, pl.txt_val

from dm.labs pl
join mas_data.patients p    
  on pl.id = p.id
  where pl.nm like '%LDL%'
  and val is not null

What I want to do is use select top n together with distinct values in the id column. Searching through some forums says to use

SELECT DISTINCT TOP 10 ...

but when I replace the first line with

SELECT DISTINCT TOP 10 p.id, pl.nm, pl.val, pl.txt_val

I get the same results as without the word distinct. What should I be doing to only get to filter out duplicate id entries?

Thank you.

Answer 1

well I wouldn't have expected it, but Halim's SELECT distinct TOP 10 MyId FROM sometable

is functionally identical to Vaishnavi Kumar's select top 10 p.id from(select distinct p.id from tablename)tablename

create table #names ([name] varchar(10))
insert into #names ([name]) values ('jim')
insert into #names ([name]) values ('jim')
insert into #names ([name]) values ('bob')
insert into #names ([name]) values ('mary')
insert into #names ([name]) values ('bob')
insert into #names ([name]) values ('mary')
insert into #names ([name]) values ('john')
insert into #names ([name]) values ('mark')
insert into #names ([name]) values ('matthew')
insert into #names ([name]) values ('luke')
insert into #names ([name]) values ('peter')

select distinct top 5 [name] from #names

select top 5 * from (select distinct [name] from #names) subquery 

drop table #names

produces the same results for both selects:

    name
1   bob
2   jim
3   john
4   luke
5   mark

it's curious that select top 5 distinct is not valid, but select distinct top 5 is and works as you might expect select top 5 distinct to work.