Oracle insert ignore duplicates

I have a table with multiple rows.  I want to have another table (identical structure) with just one row per key value (i.e. the row with the latest date).

Input data example

Red, 1/1/1906,  Color is red
Red, 7/31/2006,  Color is red

I only want one record per color.  F
or Red this would be the 7/31/2006 record.

I thought if I ran code like below that I could sort the data so the highest date would be first.  then if I loaded the results of that SQL into the new table with a unique constrainst then it would load the one with the highest date, ignoring subsequent values for color.


INSERT INTO COLORS_SINGLE (COLOR, EFFDT, DESCR)
SELECT COLOR, EFFDT, DESCR
FROM COLORS_ALL
WHERE EFF_STATUS = 'A'
ORDER BY COLOR, EFFDT desc, DESCR;


This does not work.  it fails

Any suggestions?  thanks
stirusAsked:
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sdstuberConnect With a Mentor Commented:
INSERT INTO COLORS_SINGLE (COLOR, EFFDT, DESCR)
select color,effdt,descr from
(SELECT COLOR, EFFDT, DESCR, row_number() over(partition by color order by effdt desc) rn
FROM COLORS_ALL
WHERE EFF_STATUS = 'A'
)
where rn = 1



using analytics vs aggregates allows you to partition (group) by only the color column, not the color and description.

also, they should be more efficient than querying the table twice, even if there is an index on date
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Geert GruwezOracle dbaCommented:
add a group by

INSERT INTO COLORS_SINGLE (COLOR, EFFDT, DESCR)
SELECT COLOR, MAX(EFFDT), DESCR
FROM COLORS_ALL
WHERE EFF_STATUS = 'A'
GROUP BY COLOR, DESCR
ORDER BY COLOR, EFFDT desc, DESCR;
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virtuadeptConnect With a Mentor Commented:
Your where clause needs to get the maximimum effective date and only pull those records.

INSERT INTO COLORS_SINGLE (COLOR, EFFDT, DESCR)
SELECT COLOR, EFFDT, DESCR
FROM COLORS_ALL
WHERE EFF_STATUS = 'A'
AND EFFDT = (SELECT MAX(EFFDT) FROM COLORS_ALL as B WHERE B.COLOR = COLORS_ALL.COLOR AND B.EFF_STATUS = 'A' )
ORDER BY COLOR, EFFDT desc, DESCR;

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stirusAuthor Commented:
virtuadept was good solution that solved my problem and I understood it.

sdstuber is excellent solution that also taught me something new.

so I increased points to 500 to recognize both of you.  THANIKS!
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