I found this update (done from WISQL on local FB) surprisingly slow:

update mv_li set cod_cau=(select cod_cau from mv_hd where
v_hd.n_mov=mv_li.n_mov)

Is there a better way to get the same result ?

(There is already an index on mv_hd(y_mov,n_mov) ).

TYIA

Duilio Foschi