To add to the answer.
declare
v_result clob;
begin
---- some operation on v_result
dbms_lob.substr( v_result, 4000 ,length(v_result) - 3999 );
end;
/
In dbms_lob.substr
first parameter is clob which you want to extract .
Second parameter is how much length of clob you want to extract.
Third parameter is from which word you want to extract .
In above example i know my clob size is more than 50000 , so i want last 4000 character .