Question

How can i do that?

UPDATE 
    My_Table SET my_clob = (
        SELECT 
            other_clob
        FROM 
            other_table
        WHERE 
            my_table.id = other_table.id
    );

Error:

ORA-22835: Buffer too small for CLOB to CHAR or BLOB to RAW conversion

EDIT:

Oh boy, sry guys. I turns out the column actually was a varchar(4000) in the test system i was testing doing this (in prod its a clob as it should be). Kind of makes you wonder if i was the first one to actually use the test system…

Answer 1

This is allegedly fixed in oracle 10.2. It certainly works in oracle 11g R2

If you can’t upgrade, try using some PL/SQL:

begin
  for rec in (select id, other_clob from other_table) loop
    update my_table set my_clob = rec.other_clob where id = rec.id;
  end loop;
end;
/