CREATE SEQUENCE 表名_id_seq
START WITH 1
INCREMENT BY 1
NO MINVALUE
NO MAXVALUE
CACHE 1;

//将表tb按name排序，利用row_number() over()查询序号并将该列命名为rownum，创建新表tb1并将结果保存到该表中
create table tb1 as (select *, row_number() over(order by name) as rownum from tb); 
//根据两张表共同的字段name，将tb1中rownum对应值更新到tb中num中
update tb set num=(select tb1.rownum from tb1 where tb.name = tb1.name);
//判断表tb1的存在并删除表
drop table if exists tb1;

//将表tb按name排序，利用row_number() over()查询序号并将该列命名为rownum，创建新表tb1并将结果保存到该表中
create table tb1 as (select *, row_number() over(order by name) as rownum from tb); 
//根据两张表共同的字段name，将tb1中rownum对应值更新到tb中num中，由于为0-9循环自增，则%10
update tb set num=(select tb1.rownum from tb1 where tb.name = tb1.name) % 10;
//判断表tb1的存在并删除表
drop table if exists tb1;

 do $$
 declare
 v_idx integer :=0;
 begin
 while v_idx < 10 loop
 update tb set num = v_idx;
 v_idx = v_idx + 1;
 end loop;
end $$;