SQL - Select unique multiple columns

Question

I am trying to select from a table that contains some duplicate rows like the one below:

OS	Value
A	5
A	10
B	5
B	10

I am trying to remove duplicates from both columns to get only unique values. It doesn´t matter which value will be at which OS. It should get something like this:

OS	Value
A	5
B	10

Thank you!

Does this answer your question? [Group By Multiple Columns](https://stackoverflow.com/questions/847066/group-by-multiple-columns) — INGl0R1AM0R1, Jun 02 '22 at 18:54
Unfortunately not. I Couldn´t get the result table I was expecting. I was expecting a table like in my question. — Renato Sandoval, Jun 03 '22 at 17:23

score 0 · Answer 1 · answered Jun 08 '22 at 03:33

create table DemoTable (os char(1), value smallint)
insert into demotable values ('A', 5), ('A', 10), ('B', 5), ('B', 10)
declare @i int =1
DECLARE @tempTable table (rowid int, os char(1), value smallint)

while @i<3 --this can be replaced with maximum
begin
insert into @tempTable (rowid, os, value)
values (@i, (select OS from (SELECT ROW_NUMBER() over(order by os) rowid,OS FROM DemoTable GROUP BY OS) x where rowid = @i), (select value from (SELECT ROW_NUMBER() over(order by value) rowid, value FROM DemoTable GROUP BY value) x where rowid = @i))

set @i = @i + 1
end

select os, value from @tempTable

score 0 · Answer 2 · answered Jun 08 '22 at 05:15

0

I am try solve this question, Please check my answer

SELECT * from test  group by os_1 ;

I just changed column name and table name ,you can change to your column and table name .

answered Jun 08 '22 at 05:15

Ganesan J

539
7
12

score -1 · Answer 3 · answered Jun 02 '22 at 19:04

-1

You can group by the first column and get the max value of the second:

SELECT OS, MAX(Value)
FROM oss 
GROUP BY OS

Check this DB fiddle.

answered Jun 02 '22 at 19:04

Joaquín L. Robles

6,261
10
66
96

Hi Joaquin. I want to get one of each value, not the max(value). – Renato Sandoval Jun 02 '22 at 19:25
then it looks like you'd probably have to use two tables: unique OS and unique Value – Joaquín L. Robles Jun 03 '22 at 13:00

SQL - Select unique multiple columns

3 Answers3