Update multiple columns from another table

Anyone has experience of this? a newbie wants to learn. I have tried   Update Atable a
  set ( col1, col2, col3 )

• ( select col1, col2, col3 from Btable where col4 = a.col4 ) where col5= "val"

I have put index on unique col4 on both tables. however not only the return was very very slow, the number of updated row are more than supposed to. ( ex. Atable has 20K row, Btable has 5k rows . The total rows updated are 20K rahter 5K. Somthing is not right). Appreciate anyone can help.

C Chang Received on Wed Sep 13 2000 - 23:40:49 CDT