SELECT seems to ignore a space

Question

Hi:
I'm hoping someone can shed some light on this strange case.
A table is being loaded from a 3-party source. One column is a 5-digit identifier. For whatever reason a space is coming in as a 6th character. Let's ignore the fact that we can fix the problem on the in-coming load.
I know the field has 6 chars: the LENGTH(identifier) returns 6. The ASCII(SUBSTR(identifier,6,1)) returns 32.
The strange thing is, in TOAD if I SELECT from the table where identifier = '12345' (no space at the end), I receive records. It seems that there's an automatic TRIM being applied.
I understand there are several ways around the problem of the extra space, but I'm curious about what I'm seeing.
Any thoughts?
Thanks.

Answer 1

mchrist wrote:
A table is being loaded from a 3-party source. One column is a 5-digit identifier. For whatever reason a space is coming in as a 6th character. Well, most likely column you use to store 5-digit identifier is declared as string. You did not explain how data is loaded, but most likely there is number to string conversion involved using TO_CHAR. By default, TO_CHAR number conversion to string result will have minus sign on the left for negative numbers or space for 0 and positive numbers. You need to use FM format modifier to remove that space:
SQL> select '[' || to_char(12345,'99999') || ']' from dual
  2  /
'['||TO_
[ 12345]
SQL> select '[' || to_char(12345,'FM99999') || ']' from dual
  2  /
'['||TO_
[12345]
SQL>  Also, I assume you always want 5 character identifier string. Then you need to use 0 format element, not 9:
SQL> select '[' || to_char(123,'FM99999') || ']' from dual
  2  /
'['||TO_
[123]
SQL> select '[' || to_char(123,'FM00000') || ']' from dual
  2  /
'['||TO_
[00123]
SQL> SY.
P.S. Correct solution, IMHO, would be declaring column as NUMBER(5).