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Message Posted: Tue, 28 Oct 2003 @ 15:42:59 GMT

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Not sure exactly what you're after, but...

In a merge join (as with a lot of joins in Teradata) the first value on each row that gets compared is the rowhash value.

-- If these do not match then the data values WILL NOT join.

-- If these values do match then the data values themselves are compared to see whether the two rows really do meet the join criteria If they do then the relevant columns from each row are combined into a row for the next step.

If you want fuller details on how Teradata performs a merge join then you may want to take some Teradata courses (Advanced SQL covers this, and I think Application development does as well).

Cheers,

Dave

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