CREATE OR REPLACE FORCE VIEW "FORM_FRSQ"."V_test_XML_L" ("ID", "XMLCONTENT") AS 
  SELECT 1,(

      select XMLSerialize
         (
          CONTENT
           XMLElement
           (
             "projectDetails",
                XMLELEMENT ("projectDetailsTitle",(select 1 from dual) )
           )          
         )
         from dual
  ).getclobval ()

from dual
;

SQL>   SELECT 1,(
  2        select XMLSerialize
  3           (
  4            CONTENT
  5             XMLElement
  6             (
  7               "projectDetails",
  8                  XMLELEMENT ("projectDetailsTitle",(select 1 from dual) )
  9             )          
 10           )
 11           from dual
 12    ).getclobval ()
 13  from dual
 14  ;
  ).getclobval ()
   *
ERROR at line 12:
ORA-00923: FROM keyword not found where expected

SQL> SELECT 1,(
  2      select XMLSerialize
  3         (
  4          CONTENT
  5           XMLElement
  6           (
  7             "projectDetails",
  8                XMLELEMENT ("projectDetailsTitle",(select 1 from dual) )
  9           )          
 10         )
 11         from dual)
 12  from dual
 13  ;
         1
----------
(SELECTXMLSERIALIZE(CONTENTXMLELEMENT("PROJECTDETAILS",XMLELEMENT("PROJECTDETAILSTITLE",(SELECT1FROMDUAL))))FROMDUAL)
------------------------------------------------------------------------------------------------------------------------
         1
<projectDetails><projectDetailsTitle>1</projectDetailsTitle></projectDetails>

1 row selected.