CLOB REPLACE Function from http://www.astral-consultancy.co.uk/cgi-bin/hunbug/doco.cgi?11080

gistfile1.sql

CREATE OR REPLACE FUNCTION dfn_clobReplace
( p_clob          IN CLOB,
  p_what          IN VARCHAR2,
  p_with          IN VARCHAR2 ) RETURN CLOB IS

  c_whatLen       CONSTANT PLS_INTEGER := LENGTH(p_what);
  c_withLen       CONSTANT PLS_INTEGER := LENGTH(p_with);

  l_return        CLOB;
  l_segment       CLOB;
  l_pos           PLS_INTEGER := 1-c_withLen;
  l_offset        PLS_INTEGER := 1;

BEGIN

  IF p_what IS NOT NULL THEN
    WHILE l_offset < DBMS_LOB.GETLENGTH(p_clob) LOOP
      l_segment := DBMS_LOB.SUBSTR(p_clob,32767,l_offset);
      LOOP
        l_pos := DBMS_LOB.INSTR(l_segment,p_what,l_pos+c_withLen);
        EXIT WHEN (NVL(l_pos,0) = 0) OR (l_pos = 32767-c_withLen);
        l_segment := TO_CLOB( DBMS_LOB.SUBSTR(l_segment,l_pos-1)
                            ||p_with
                            ||DBMS_LOB.SUBSTR(l_segment,32767-c_whatLen-l_pos-c_whatLen+1,l_pos+c_whatLen));
      END LOOP;
      l_return := l_return||l_segment;
      l_offset := l_offset + 32767 - c_whatLen;
    END LOOP;
  END IF;

  RETURN(l_return);

END;
/