Insert statement taking a very long time to complete

[I recently posted this on .server; I apologize for the double- posting.]

I'm having some trouble with an SQL insert statement taking waaay too long to run. It's been suggested that maybe I'm using inefficient SQL, and that there might be a faster way to achieve the results.

I have two tables with identical structure, and I want to copy all records that exist in table A but not in table B, into table B.

Assuming that the structure is primary key "pk" and data fields "f1", "f2" and "f3", here is the SQL statement I'm using:

  insert into tableb(pk, f1, f2, f3)
  (select * from tablea where tablea.pk not in (select pk from tableb))

This statement has worked well for small amounts of data, but when I tried on a table with approximately 200k records, it took forever to finish.

A coworker with some SQL experience thinks that the "where" clause is being executed for *every* insertion. If so, this could certainly account for much of the slowdown.

Anyone have any suggestions?

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John Gordon                   A is for Amy, who fell down the stairs
gordon_at_panix.com              B is for Basil, assaulted by bears
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