SQL Query by row number based on category

did yiu need sothing like this

Select col1,col2,min(colc) from tablename
Group by col1,col2

but it's not numerical column, it's string

please read this article to solve the issue:
https://www.experts-exchange.com/A_3203.html

to get the result as per your requirment you need to do it like this

Is there any numarical unique id in the table ??

IF yes then you can query like this ..assume colId as unique numarical column

select colid ,col1,col2,colc from tablename
where colid in
(
Select min(colid ) from tablename
Group by col1,col2 )

my table didn't contains unique key and  numerical column, any suggestion????

Exactly how do you define first row/entry for that column?  The first one actually inserted?  I don't think you will be able to get consistent results with that.  For standard heap tables Oracle will just insert data where it can, and physical arrangement can and will change, especially when you backup/restore/transfer data.

Suggest you take time to add a numerical column and assign numbers for each row.  For maintenance, use a sequence to automatically assign the value of your numerical column upon insert of new data.  This way you can now a query like the one mentioned by pratima

thks i got the solution by using following method :
ROW_NUMBER() OVER ( PARTITION BY AREA,IE_RESOURCE,FW_RESOURCE, STEP, TECH ORDER BY AREA,IE_RESOURCE,FW_RESOURCE,STEP,TECH ASC ) rn

This is my SQL:
SELECT DISTINCT AREA,IE_RESOURCE,FW_RESOURCE, STEP,TECH, RECIPE
FROM
(
SELECT DISTINCT AREA,IE_RESOURCE,FW_RESOURCE, STEP,TECH, RECIPE, DEVICE,
ROW_NUMBER() OVER ( PARTITION BY AREA,IE_RESOURCE,FW_RESOURCE, STEP, TECH ORDER BY AREA,IE_RESOURCE,FW_RESOURCE,STEP,TECH ASC ) rn
FROM (
SELECT   SUBSTR(A.IE_RESOURCE,0,3) AS AREA , A.TECH AS TECH,  A.STEP AS STEP, A.FW_RESOURCE AS FW_RESOURCE, A.IE_RESOURCE AS IE_RESOURCE , A.RECIPE AS  RECIPE,A.DEVICE AS  DEVICE
FROM IEDC_TECH_WPH_R2_TST A
WHERE ( A.REMARKS NOT  LIKE '%Step-NotActive%' OR A.REMARKS IS NULL)
UNION
SELECT  SUBSTR(B.IE_RESOURCE,0,3) AS AREA, B.TECH AS TECH,  B.STEP AS STEP, B.FW_RESOURCE AS FW_RESOURCE, B.IE_RESOURCE AS IE_RESOURCE,B.RECIPE AS  RECIPE,B.DEVICE AS  DEVICE
FROM IEDC_TECH_WPH_R2ALT B
WHERE ( B.REMARKS NOT  LIKE '%Step-NotActive%' OR B.REMARKS IS NULL)
)
)
WHERE rn = 1
ORDER BY AREA,IE_RESOURCE,FW_RESOURCE, STEP,RECIPE, TECH

Anyway how to add where condition in

ROW_NUMBER() OVER ( PARTITION BY AREA,IE_RESOURCE,FW_RESOURCE, STEP, TECH ORDER BY AREA,IE_RESOURCE,FW_RESOURCE,STEP,TECH ASC ) rn

i just row number WHERE DEVICE = 'DEFAULT'

Pls help.

can you please clarify with output samples of what you get and what you want?
I am not 100% sure ...