Getting CLOB completed from DB table via SQL in Oracle - sql

Question

I have a table (actually a view) with few varchar2 fields. Say,
v_report(id, name, profile_id, profile_name);
I need to collect id-groupped data into a string. So, I do:
SELECT
id,
'Name: ' || clobagg(DISTINCT name)
|| ' Profile_name: ' || clobagg(DISTINCT profile_name)
as description
FROM
v_report
GROUP BY
id
clobagg is like described here: https://community.oracle.com/thread/2264483
(especially use clobagg not stragg due to it's returning value clob able to store >4000 chars)
It works fine when concatenated profile string isn't too large. But if it is i get fair Oracle exception:
ORA-22835: Buffer too small for CLOB to CHAR or BLOB to RAW conversion (actual: 7680, maximum: 4000)
Is there some way out? I mean something like DBMS_LOB.APPEND function but available to call via SQL. Or any other way to concat many varchar2 strings into a large CLOB string w/o length limit.
Thanks in advance.
Pavel.

Answer 1

NOTE: initially posted as a Comment, but offered as an Answer now, since the OP has confirmed that this was, in fact, the problem.
So, are you able to create the CLOBs in the first place (without concatenation)? If you are, then what you are missing is wrapping the literals (and any other VARCHAR2 values you may have) within to_clob(). Good luck!

Answer 2

Minor addition.
After this solving I got same error in clobagg;
So I had to modify it to set input parameter as varchar2 (to enable DISTINCT clause work) and the returning value is CLOB.
So, as far it may be useful here it is:
create or replace
TYPE CLOBAGG_TYPE AS OBJECT
(
text clob,
static function ODCIAggregateInitialize(
sctx in out clobagg_type
)
return number,
member function ODCIAggregateIterate(
self in out clobagg_type,
value in varchar2
)
return number,
member function ODCIAggregateTerminate(
self in clobagg_type,
returnvalue out clob,
flags in varchar2
)
return number,
member function ODCIAggregateMerge(
self in out clobagg_type,
ctx2 in clobagg_type
)
return number
)
create or replace
TYPE BODY CLOBAGG_TYPE AS
static function ODCIAggregateInitialize(
sctx in out clobagg_type
)
return number
is
begin
sctx := clobagg_type(null) ;
return ODCIConst.Success ;
end;
member function ODCIAggregateIterate(
self in out clobagg_type,
value in varchar2
)
return number
is
begin
self.text := self.text || ', ' || value;
return ODCIConst.Success;
end;
member function ODCIAggregateTerminate(
self in clobagg_type,
returnvalue out clob,
flags in varchar2
)
return number
is
begin
returnValue := ltrim(self.text,', ');
return ODCIConst.Success;
end;
member function ODCIAggregateMerge(
self in out clobagg_type ,
ctx2 in clobagg_type
)
return number
is
begin
self.text := self.text || ctx2.text;
return ODCIConst.Success;
end;
END;
create or replace
FUNCTION CLOBAGG(
input varchar2
) RETURN clob
deterministic
parallel_enable
aggregate using clobagg_type;