sqlfiddle: leading blanks are gone I am not sure if this is on topic here. 

When selecting VARCHAR2 columns that contain values with leading blanks this leading blanks will not be displayed in the output of sqlfiddle. so

select '     x' from dual


gives some html equivalent to 

+-------------+
|"X"          |
+-------------+
|x            |
+-------------+


(without preceding blanks).

Here is the ouput in sqlfiddle.

A workaround is

SELECT translate('     x',' ',chr(128)) FROM dual
/


copy and paste the output to a spreadsheet 
and then substitute this character by a blank. 

Is there a better way get tproper output?
Response from admin@sqlfiddle.com (originally provided by miracle173 in a comment):

If you change the output format to &quot;plaintext&quot; rather than &quot;tabular&quot; (the default) you'll see the whitespace there like you expect. You can change the format by clicking the down arrow next to &quot;Run SQL&quot;.
The reason you aren't seeing it in tabular mode is because by default html ignores more than one whitespace character, and I'm not bothering to do any work to override this default behavior for tabular formatting.