deleting rows from one table when they exist in another

A project I'm working on has a daily update of a table and then reapplies
each day a table of updates called EditHistory.
What's the best way to do this while avoiding duplicate rows.
I want to copy all rows from the table that's been updated, then remove any
records that just came in that are also in EditHistory and then copy the
ones from EditHistory in. This way I'll be left with a combination of the
records that were never edited along with the ones that have been edited but
the ones have been changed would be gone because the ones from EditHistory
override them.
Thanks for your help.Hi Bob
The better option would be not to insert existing rows
UPDATE m
SET x = O.x, y=O.y
FROM MyTable m
JOIN MyOtherTable O ON m.PK = O.PK
INSERT MyTable ( PK, x , y )
SELECT O.PK, O.x, O.y
FROM myOtherTable O
LEFT JOIN MyTable m ON m.PK = O.PK
WHERE m.PK IS NULL
John
"bob" wrote:
> A project I'm working on has a daily update of a table and then reapplies
> each day a table of updates called EditHistory.
> What's the best way to do this while avoiding duplicate rows.
> I want to copy all rows from the table that's been updated, then remove any
> records that just came in that are also in EditHistory and then copy the
> ones from EditHistory in. This way I'll be left with a combination of the
> records that were never edited along with the ones that have been edited but
> the ones have been changed would be gone because the ones from EditHistory
> override them.
> Thanks for your help.
>
>