XML Query on a CLOB Column

Question

I am trying to query a column which is of CLOB data type,in Oracle, and My Data is stored something like this
<Result><Institution>XXX</Institution><Application>XXX</Application><ID>123123123</ID><SequenceID>MSGID123123</SequenceID><DateTime></DateTime></Result>
I am trying to run the xquery on this like this
SELECT Message FROM LOGS
('for $i in ora:view("LOGS")
where $i/Result/Institution/ = 'XXX'
return $i/Result/Institution/
PASSING :Institution AS 'XXX').
I either get exception that "missing right parenthesis" or doesnt execute at all.
My Table "LOGS" as the Columns Message as CLOB.
Any Ideas how to query on this kind of columns in a table in Oracle using XQuery?
Cheers
Sridhar

Answer 1

Hi,
First of all, please always give your database version (all digits from "select * from v$version").
Oracle XML support is achieved through the XMLType datatype, so you must first convert any string variable (CLOB, VARCHAR2) holding XML data to that type in order to use XML-related functions.
Now, to the point, if you want to check the existence of a particular node, you can try the following :
-- if Institution may occur multiple times :
select message
from logs
where existsnode(xmltype(message), '/Result[Institution="'||:p_institution||'"]') = 1
-- if only one Institution element is expected :
select message
from logs
where extractvalue(xmltype(message), '/Result/Institution') = :p_institution
;And the 11g equivalent :
select message
from logs
where xmlexists('$d/Result[Institution=$p]' passing xmltype(message) as "d", :p_institution as "p")
select message
from logs
where xmlcast(
        xmlquery('$d/Result/Institution' passing xmltype(message) as "d" returning content)
        as varchar2(30)
      ) = :p_institution
;