Sorting by XML tag

Question

I am using Oracle 8i for storing XML files in a CLOB column and that column is intermedia text indexed. Is there any way to sort a query output based on an XML tag within that CLOB column. for eg., <price>10.22</price> is an XML tag, can i sort on price

Answer 1

I don't think you'll be able to use interMedia text directly to sort the query output, but you should be able to use dbms_lob.instr and dbms_lob.substr to look for a specific tag and then sort on the contents of the tag. It may not be pretty, but you could do something like:
select fields
from xmltable
where <where clause>
order by
nvl(dbms_lob.substr(
clobcolumn,
dbms_lob.instr(clobcolumn, '</price>') - dbms_lob.instr(clobcolumn, '<price>'),
dbms_lob.instr(clobcolumn, '<price>')), 0) asc/desc
You'd have to test it out, but the above should return the peice between the <price> and the </price> tags, or 0 if the tags don't exist.