create table new_a
as
select a.a_key,a.a_values,a.a_dec
from a
where rowid = (select min(rowid) from a where a_key=a.a_key and a_values=a.a_values)
as
select a.a_key,a.a_values,a.a_dec
from a
where rowid = (select min(rowid) from a where a_key=a.a_key and a_values=a.a_values)
alter table new_a add primary key (a_key,a_values)