Question

我在postgres中有id列，它不是整数的串行。它有1到3个值，而此列的行超过100.我想通过查询不断地将值分配给空行为4,5,6。这是一个例子，虽然我在表中有很多记录。所以帮助我如何使用查询更新id列

select id, name from xyz order by id;  

            id | name
            1  | a
            2  | b
            3  | c
               | d
               | e
               | f

想要的结果

select id, name from xyz order by id;

    id | name
    1  | a
    2  | b
    3  | c
    4  | d
    5  | e
    6  | f

以下仅针对提交问题的行，请不要考虑：

select id ,name,date_time,(select 'wasa'::text) as link from abc 
union
select x.id+max(a.id),x.name,x.date_time,(select 'uu'::text) as link from xyz x ,abc a
group by x.id
order by id

Answer 1

select count(id) into temp_count 
from table_name ;

select id into temp_id
from table_name order by id asc limit 1;

while (temp_id <=temp_count)
Do
    set temp_last_id = (select id from table_name where id is not null order by id desc limit 1);
    update table_name
    set  id = temp_last_id +1;

    set temp_id =temp_id +1;
end while;

Answer 2

从表中查找id的最大可用值

Select max(id) from xyz

假设其值为3.创建序列并将最大值+ 1分配为

CREATE SEQUENCE seq START 4;

使用序列

更新空ID

Update xyz
SET id = nextval('seq')
WHERE id IS NULL;

Answer 3

您可以使用一个update语句执行此操作：

update xyz
  set id = t.rn
from (
  select ctid, 
         row_number() over (order by name) + (select count(*) from xyz where id is not null) as rn
  from xyz
  where xyz.id is null
) t
where t.ctid = xyz.ctid;

请注意＆＃34;序列＆＃34; ID无法保证，但如果您只想生成一个唯一值，则无关紧要。

增加列值手册

3 个答案: