Help with counting XML elements and converting from MS SQL 2008 to ORACLE

Question

Hello,
My ORACLE DB version is:
('Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production');
('PL/SQL Release 11.2.0.2.0 - Production');
('CORE     11.2.0.2.0     Production');
('TNS for Linux: Version 11.2.0.2.0 - Production');
('NLSRTL Version 11.2.0.2.0 - Production');
I'm trying to convert the below SQL Server 2008 query to work on Oracle. It's important to note that the XMLData column type is CLOB.
Query 1)
-- Number of validations
select br.rulename, CAST(( CAST(br.XMLData as XML)).query('count(//Validation/Expressions/Expression)') as nvarchar(50)) as "Number of //Validation/Expressions/Expression"
from AsBusinessRules br
where
DATALENGTH(br.XMLData)>10
and CAST(( CAST(br.XMLData as XML)).query('count(//Validation/Expressions/Expression)') as nvarchar(50)) not like '0'
Any help is greatly appreciated.

Answer 1

Hi,
You can try one of these :
select br.rulename
     , count(*) as "Num. of Expression"
from AsBusinessRules br
   , xmltable(
       '//Validation/Expressions/Expression'
       passing xmltype(br.XMLData)
     ) x
where length(br.XMLData) > 10
group by br.rulename
having count(*) != 0
;or,
select br.rulename
     , xmlcast(
         xmlquery(
           'count(//Validation/Expressions/Expression)'
           passing xmltype(br.XMLData)
           returning content
         as number
       ) as "Num. of Expression"
from AsBusinessRules br
where length(br.XMLData) > 10
and xmlcast(
      xmlquery(
        'count(//Validation/Expressions/Expression)'
        passing xmltype(br.XMLData)
        returning content
      as number
    ) != 0
It's important to note that the XMLData column type is CLOB.Could you consider migrating the column to XMLType datatype?
Given your version, it would be binary XML by default and therefore a lot more performant with XQueries, compared to a simple CLOB storage.