修剪后未删除尾随 space

Question

我运行这个查询：

select trim(utl_raw.cast_to_varchar2((nlssort(d.det_entete, 'nls_sort=binary_ai')))) entete,
length(trim(utl_raw.cast_to_varchar2((nlssort(d.det_entete, 'nls_sort=binary_ai'))))) nb 
from details_param_import d join param_import_table p on d.param_code = p.param_code;

它给出了这个结果：

那么如何删除尾随 space 呢？

Answer 1

如果您 dump() 修改后的值，您可以看到末尾有一个空字节，而不是 space；并且 length() 仍然将其视为一个字符：

column entete format a20
column bytes format a40

with details_param_import (det_entete) as (
  select 'nom' from dual
  union all select 'prenom' from dual
)
select trim(utl_raw.cast_to_varchar2((nlssort(d.det_entete, 'nls_sort=binary_ai')))) entete,
length(trim(utl_raw.cast_to_varchar2((nlssort(d.det_entete, 'nls_sort=binary_ai'))))) nb,
  dump(trim(utl_raw.cast_to_varchar2((nlssort(d.det_entete, 'nls_sort=binary_ai'))))) bytes
from details_param_import d
/

ENTETE                       NB BYTES                                   
-------------------- ---------- ----------------------------------------
nom                           4 Typ=1 Len=4: 110,111,109,0              
prenom                        7 Typ=1 Len=7: 112,114,101,110,111,109,0

也就是 .

您可以明确地trim关闭：

with details_param_import (det_entete) as (
  select 'nom' from dual
  union all select 'prenom' from dual
)
select rtrim(utl_raw.cast_to_varchar2((nlssort(d.det_entete, 'nls_sort=binary_ai'))), chr(0)) entete,
length(rtrim(utl_raw.cast_to_varchar2((nlssort(d.det_entete, 'nls_sort=binary_ai'))), chr(0))) nb,
  dump(rtrim(utl_raw.cast_to_varchar2((nlssort(d.det_entete, 'nls_sort=binary_ai'))), chr(0))) bytes
from details_param_import d
/

ENTETE                       NB BYTES                                   
-------------------- ---------- ----------------------------------------
nom                           3 Typ=1 Len=3: 110,111,109                
prenom                        6 Typ=1 Len=6: 112,114,101,110,111,109

这对你真正想做的事情是否有用是另一回事；查询归类键，而不是将其用于排序或比较，可能没有多大用处。您似乎正在使用它来删除字符串中的重音符号，但较长的值可能会被截断 (as the docs mention)，即使对于较短的字符串，它似乎也不能保证您最终会得到您期望的结果。所以，如果有一天它坏了，请不要太惊讶。

修剪后未删除尾随 space

Trailing space is not removed after trimming

oracle

oracle11g

oracle11gr2