Question

I have a table that looks like this:

id,  col1,   col2   col3
0    "Goat"  "10"   "0"
1    "Cat"   "11"   "0"
2    "Goat"  "12"   "1"
3    "Mouse" "13"   "0"
4    "Cat"   "14"   "2"

I want be able to return the UNIQUE values in Col1 AND if there are two identical values in col1 then use col3 to decide which value to use i.e. if it has a ‘0’ in col3.

So I should get a table like this:

id,  col1,   col2   col3
0    "Goat"  "10"   "0"
1    "Cat"   "11"   "0"
3    "Mouse" "13"   "0"

Hope this makes sense?

Thank you

Answer 1

Read about ROW_NUMBER() OVER(): http://msdn.microsoft.com/en-us/library/ms186734.aspx

You have to select rows, where ROW_NUMBER() OVER(PARTITION BY col1 ORDER BY col3) is 1:

select *
from 
(select
  id, 
  col1, 
  col2, 
  col3,
  ROW_NUMBER() OVER(PARTITION BY col1 ORDER BY col3) nom
from table_name) a
where a.nom = 1