Logic on UPDATE query

I am dealing with two tables and I am trying to take one column from a table and match the records with another table and append the data of that column.

I used an update query that looks like this:

UPDATE Acct_table Set Acct_table.Score =
(Select Score_tbl.Score from Score_tbl
Where Acct_table.Acctnb = Score_tbl.Acctnb

This process has been running for over an hour and a half and is building a large log file. I am curious to know if there is a better command that I can use in order to join the tables and then just drop the column from one to the other. Both tables are indexed on Acctnb.

Any insight would truly help.
Thanks!UPDATE A Set A.Score = S.Score
from Acct_table A
JOIN Score_tbl S
ON A.Acctnb = S.Acctnb|||Does anyone else hear an echo?|||Does anyone else hear an echo?No, not a thing. Why?

Yes, I deleted Thrasy's duplicated post

-PatP|||aaaaaaaaaa