Find all records that have character alone in a string

Question

Oracle 10g Enterprise Edition
Hi all,
I must select from a varchar2 field, all the records that have a character (number or char) alone in the string.
For example.
ASDF BHGR H RR (yes, cause "H")
ASDF BHGR H4 R (yes, cause "R")
ASDF B H4 DDR (yes, cause "B")
ASDF B H4 DDR (yes, cause "B")
ASDF BC 1 DDR (yes, cause "1")
ASDF BC / DDR (yes, cause "/")
ASDF BHGR H4 RR (no)
ASDF (no)
I'm trying by SubStr, but I cannot generally solutions.
Thank's for any suggestion.
Ciao

Answer 1

Ok, just a try :
SQL> with tbl as
  2  (select 'ASDF BHGR H RR' str from dual union all
  3   select 'ASDF BHGR H4 R' str from dual union all
  4   select 'ASDF B H4 DDR' str from dual union all
  5   select 'ASDF BHGR H4 R1' str from dual union all
  6   select 'ASDF BHGR H4' str from dual union all
  7   select 'ASDF - H4' str from dual union all
  8   select 'a1 ASDF BHGR H4' str from dual union all
  9   select 'ASDF B H4 DDR' str from dual union all
10   select 'ASDF BC 1 DDR' str from dual union all
11   select 'ASDF BC / DDR' str from dual)
12  select str,
13         decode(regexp_instr(str,'^. | . | .$'),0,'no',decode(regexp_instr(str,'^- | - | -$'),0,'yes','no')) res
14  from tbl;
STR             RES
ASDF BHGR H RR  yes
ASDF BHGR H4 R  yes
ASDF B H4 DDR   yes
ASDF BHGR H4 R1 no
ASDF BHGR H4    no
ASDF - H4       no
a1 ASDF BHGR H4 no
ASDF B H4 DDR   yes
ASDF BC 1 DDR   yes
ASDF BC / DDR   yes
10 rows selected.May is there is a simpler way.
Nicolas.