DevOps, CI/CD and Automation

Hello! I'm trying to use the code in a View in order to return the sum of amount in a column. However, I want to do a JOIN so that I can pass a parameter from the main query to the subquery as follows.

create view  
    view_test  
as  
select  
a.column1,  
a.column2,  
  
(select sum(amtval)  
from example,  
    xmltable(  
        'for $r in /row  
            for $c2 in $r/c2  
                let $m2 := $c2/@m  
                let $c5 := $r/c5[@m=$m2]  
                where exists($c5)  
                    return <amt> {$c2} {$c5} </amt>'  
    passing yourdata  
    columns   
        amount varchar2(10) path 'c2',  
        amtval number(10,2) path 'number(c5)'  
    )  
where amount = a.column2),  
  
a.column3  
from  
test_table a;

I am getting invalid identifier error when trying to do so (where amount = a.column2). How do I modify the query so that I can do the join on the other table?