sql - 如何对 oracle 表 id 重新排序

Question

我有一个这样的 Oracle 表：

fruit    id
-------- -----
apple     1
plum      9
pear      55
orange    104
..

id 列号错误。如何更新每行的 id 以重新排序，如下所示：

fruit    id
-------- -----
apple     1
plum      2
pear      3
orange    4

最有效的方法是什么？

Answer 1

update your_table
set id = rownum

Answer 2

如果您需要保证旧订单，则应执行以下操作：

merge into the_table 
using
( 
   select rowid as rid, 
          row_number() over (order by id asc) as new_id
   from the_table
) t on (t.rid = the_table.rowid) 
when matched then 
  update set id = new_id;

Answer 3

DECLARE
i INTEGER :=1;
BEGIN;
    FOR n IN (SELECT your_primary_id  FROM your_table_name ORDER BY your_primary_id);
    LOOP;
        UPDATE your_table_name 
          SET your_primary_id=i 
          WHERE your_primary_id = n.your_primary_id;
        i := i + 1;
    END LOOP;
END;
/