Duplicate values Re-Posted

[rez3366]

Please ignore the previous post as it is not correct.
I have a table with the following structure :

NGP NPA ZIP Dfault

"AAR" "734" "48104" ""
"ABA" "256" "35951" ""
"ABC" "626" "91770" ""
"ABL" "325" "79607" ""
"ABL" "915" "79607" ""
"ABN" "253" "98003" ""
"ABY" "541" "97321" ""
"ACA" "256" "35010" ""
"ACC" "805" "93422" ""
"ACT" "978" "02119" ""
"ADR" "517" "49221" ""
"AFW" "682" "76012" ""
"AFW" "817" "76014 " "Y"
"AGA" "229" "31707" ""
"AGC" "805" "93420" ""
"AHC" "224" "60005 " "Y"
"AHI" "847" "60005" "Y"
"AHD", "888" "60005" ""

I need to extract unique values based on the third column
NGP. So for example there are 3 instances of "6005" and I need to have only one of those pulled from the table.
A distinct statement will not work.
Many thanks in advance.

 

[nagornyi]

Since it does not matter which record to pick of those with the same NGP, you may select the one with maximum value of NPA.

select 
  a.NGP
, a.NPA
, (select ZIP from table where NGP=a.NGP and NPA=a.NPA and Dfault='Y') ZIP
from
(select distinct NGP,max(NPA) NPA from table where Dfault='Y' group by NGP) a