ORA-21560: 参数 2 为空、无效或超出范围

Question

create table test_clob
(
    id number,
    text clob
);

insert into test_clob values
(2,'Hi This can be a value that is too much old');

select * from test_clob;

SET serveroutput ON;
DECLARE
  vlength pls_integer;
  text_cbl CLOB;
  Var_temp1 VARCHAR2(1024);
  starti    number := 1;
  offset number:= 1;
  val pls_integer;
  amt pls_integer := 0;
BEGIN
  SELECT text INTO text_cbl FROM test_clob WHERE id = 2;
  vlength     := SYS.DBMS_lob.getlength(text_cbl);
  WHILE(starti < vlength)
  LOOP
      val := sys.dbms_lob.instr(text_cbl,chr(32),offset);
      amt := val - offset;
      sys.dbms_lob.read(text_cbl,amt,starti,Var_temp1);
      dbms_output.put_line(Var_temp1);
      offset := val;
      starti := val + 1;
  END LOOP;
END;

Answer 1

在某些时候会有行尾或文本没有空格 ch ( 32) 所以在那个时候它返回 val offset then read。