A、create index idx1_test on test(object_id); select count(*) from test where object_id is not null; C、create index idx2_test on test(object_id,0); select count(*) from test; D、create index idx2_test on test(object_id,0); select count(*) from test where object_id is not null; E、create index idx1_test on test(object_id); select count(object_id) from test;