length()问题求教？

Question

字段id是Varchar2类型,
例如
id1 = "123456789012345678"
id2 = "１２３４５６７８９０１２３４５６７８"
使用如下语句：
select * from  t
where length((t.id))>18
结果不显示id2，
试问修改上面的语句怎么显示id2的结果啊？

Answer 1

SQL> create table a
  2  ( a1 char(50),
  3     a2 varchar2(50));表已创建。SQL> insert into a values 
      ('123456789012345678',
       '１２３４５６７８９０１２３４５６７８');已创建 1 行。SQL> commit;提交完成。SQL> select length(a1),length(a2) from a;LENGTH(A1) LENGTH(A2)    
---------- ----------   
        50         18   SQL> select length(trim(a1)),length(trim(a2) from a;
select length(trim(a1)),length(trim(a2) from a
                                        *
ERROR 位于第 1 行: 
ORA-00907: 缺少右括号 
SQL> select length(trim(a1)),length(trim(a2)) from a;LENGTH(TRIM(A1)) LENGTH(TRIM(A2))        
---------------- ----------------           
              18               18

Answer 2

我是想怎么将id2的结果删除，并且保留id1,因为length()的结果一样,所以无从下手

Answer 3

SQL> create table a
  2  ( id varchar2(50) ) ;表已创建。SQL> insert into a values
  2   ('123456789012345678');已创建 1 行。SQL> insert into a values
  2   ('１２３４５６７８９０１２３４５６７８');已创建 1 行。SQL> commit;提交完成。SQL> select id,length(id) from a;ID                                                 LENGTH(ID)                   
-------------------------------------------------- ----------                   
123456789012345678                                         18                   
１２３４５６７８９０１２３４５６７８                       18                   SQL> select id,vsize(id) from a;ID                                                  VSIZE(ID)                   
-------------------------------------------------- ----------                   
123456789012345678                                         18                   
１２３４５６７８９０１２３４５６７８                       36

Answer 4

select * from  t
where lengthb((t.id))>18
用lengthb()判断全角