Question

我想在_列中删除所有name前缀，但结果可能会导致冲突。因此，如果结果与现有结果重复，我希望为其添加_后缀，直到没有重复。

在下面的示例中，_test应重命名为test___。

create table A  
(  
  name  VARCHAR2(20) unique,  
  id int  
);  
insert into a (name, id) values ('_test', 1);  
insert into a (name, id) values ('test', 2);  
insert into a (name, id) values ('test_', 3);  
insert into a (name, id) values ('test__', 4);

Answer 1

试试这个：

merge into A
using (with aa as (select id, trim('_' from name) name from A)
     select rpad(name,
               length(name) - 1 + row_number()
               over(partition by name order by id),
               '_') name2,
          id
     from AA) s
on (s.id = a.id)
when matched then
  update set a.name = s.name2

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