create sequence fl_user_seq increment by 1 minvalue 1 no maxvalue start with 1;

select setval('fl_user_seq ', 88);

CREATE SEQUENCE if not exists test_mergetable_id_seq
INCREMENT 1
MINVALUE 1
MAXVALUE 999999999
START 1
CACHE 1;
//或者： 
create sequence if not exists test_mergetable_id_seq increment by 1 minvalue 1 no maxvalue start with 1; 

alter table test_mergetable alter column "i_id" set default nextval('test_mergetable_id_seq');

SELECT setval('test_mergetable_id_seq', (SELECT MAX(i_id) FROM test_mergetable));
alter sequence test_mergetable_id_seq start with 12;

drop sequence IF EXISTS test_mergetable_id_seq

SELECT nextval('test_mergetable_id_seq')