I have the below SQL query but it gives the error message ORA-00904: "KUST_ADR"."KU_NR": invalid identifier
even though those are the correct table and column names. What else could be the cause?
update auf_adr
set email = (select k.ku_email
from auf_kopf k join
kust_adr ka
on k.kunr = ka.ku_nr
where auf_adr.auf_nr = k.auf_nr and
ka.ku_adr_art = 1 and
auf_adr.email <> ka.ku_email and
(select sum(s.rg_anz)
from auf_stat s
where s.auf_nr = k.auf_nr
) = 0
)
where auf_adr.adr_art = 2 and
exists (select 1
from auf_kopf k join
kust_adr ka
on k.kunr = ka.ku_nr
where auf_adr.auf_nr = k.auf_nr and
ka.ku_adr_art = 1 and
auf_adr.email <> ka.ku_email and
(select sum(s.rg_anz)
from auf_stat s
where s.auf_nr = k.auf_nr
) = 0
);