Craig
How do I pull out all the non-duplicate records?
With an exclusion join. To find non-duplicates with respect to one key...
SELECT keycandidate
FROM tbl t1
LEFT JOIN tbl t2 ON t1.keycandidate=t2.keycandidate
WHERE t2.keycandidate IS NULL;
To expand the comparison to multiple keys...
SELECT key1, key2, ...
FROM tbl t1
LEFT JOIN tbl t2 ON t1.key1=t2.key2 AND t1.key2=t2.key2 AND ...
WHERE t2.key1 IS NULL;
PB
Weston, Craig (OFT) wrote:
Hi there,
I have a situation where I have duplicate data within
several tables, but they are all indexed in the same way. How do I pull
out all the non-duplicate records?
Would I have to create a temporary table, add one data set, then add the
second where it doesn't equal the first, and then do the same with the
third? Or is there a cleaner way?
Thanks,
Craig
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