How to remove extra spaces in a xml formatted string

Question

Hi,
I am trying to remove extra spaces between the xml tags. For
example, if a string is something like
' <header 1> <header 2> test </header 2> </header1>'
I want to get rid of the spaces only between the closing tag of header 1 and opening tag of header 2 and closing tag of header 2 and opening tag of header 1, in short ,I want to remove the extra spaces between the tags if there are no other characters between them. I do not want the remove the spaces between closing tag header 2 and opening tag of header ,as there is occurence of other characters.
I am aware that this can be done by looping through the string and using instr to identify the characters '<' and '>', but I would like to use it as a last resort only.
Can anyone suggest me a better way of doing it in a single go by manipulating the data?
Any help is really appreciated.
Regards,
Anil.

Answer 1

You can use the replace function. If you only expect one extra space, then:
scott@ORA92> select replace ('<header 1> <header 2> test </header 2> </header1>',
2      '><', '><')
3 from dual
4 /
REPLACE('<HEADER1><HEADER2>TEST</HEADER2></HEADER
<header 1> <header 2> test </header 2> </header1>
If you expect more extra spaces, then you will need to wrap another replace function around it for each space, for example the following will eliminate up to three spaces:
scott@ORA92> select replace (replace (replace ('<header 1> <header 2> test </header 2> </header1>',
2      '>     <', '><'), '>     <', '><'), '> <', '><')
3 from dual
4 /
REPLACE(REPLACE(REPLACE('<HEADER1><HEADER2>TEST
<header 1><header 2> test </header 2></header1>