oracle xmlexists with variable path - sql

Question

I have a table tsk with 2 columns : a task id in number, and a task scope in XMLTYPE which can be like :
<scope>
<siteCode>2</siteCode>
<supplierCode>1111</supplierCode>
<contractCode>464</contractCode>
<orderNumber>85235478</orderNumber>
</scope>
But the elements under the tag may vary from one record to another
I need to select task ids which match some conditions in the scope.
For example :
select tskid
from tsk t
where xmlexists('$a/scope[siteCode = 2 and supplierCode = 111]' passing t.tskscope as "a");
As the scope may vary, I have a PL/SQL function taking a xml path p_xmlpath to look for, in varchar2 type.
So for example, p_xmlpath will be :
p_xmlpath := 'scope[siteCode = 2 and supplierCode = 1111]';
Then I want to run the query with XMLEXISTS to find the matching records.
I thought to do it with bind variables in the following way :
select tskid
from tsk t
where xmlexists('$a/$b' passing t.tskscope as "a", p_xmlpath as "b" );
By doing this, the query returns all records, without taking the condition with xmlexists.
Does someone know how to manage this, i.e. having a variable path to give to XMLEXISTS ?
Additional info : until now, I used the function existsNode and the following query was doing the job correctly:
select tskid
from tsk t
where existsnode(t.tskscope, p_xmlpath) = 1;
But on one hand existsNode is deprecated and on the other I noticed that in my situation the function xmlexists was noticeably faster than existsNode, that's why I would to switch to xmlexists.
Thanks in advance.

Answer 1

I don't think you can; it seems to only allow the search values to be variables, not the whole search condition.
As a workaround you could build the XPath at runtome with replace():
select tskid
from tsk t
where xmlexists(replace('$a/$b', '$b', p_xmlpath) passing t.tskscope as "a");
or build the XPath string as a variable if you'd rather not have a replace in there, and include the $a/ part:
p_xmlpath := '$a/' || p_xmlpath;
select tskid
from tsk t
where xmlexists(p_xmlpath passing t.tskscope as "a");