SQL查出异常数据（ORA-01722: 无效数字）

-- Created on 2015/4/29 by MENGHU 
DECLARE
  -- Local variables here
  I INTEGER;
BEGIN
  FOR OPEN_DATA IN (SELECT *
                      FROM SYS_DEPT_ACCOUNTING SDA
                     WHERE SDA.SEGMENT4 IS NOT NULL) LOOP
    BEGIN
      BEGIN
        SELECT TO_NUMBER(TRIM(SDA.SEGMENT4))
          INTO I
          FROM SYS_DEPT_ACCOUNTING SDA
         WHERE SDA.SEGMENT4 IS NOT NULL
           AND SDA.ACCOUNT_ID = OPEN_DATA.ACCOUNT_ID;
      EXCEPTION
        WHEN OTHERS THEN
          NULL;
          INSERT INTO TEMP_T1 (A1) VALUES (OPEN_DATA.ACCOUNT_ID);
      END;
    END;
  END LOOP;
END;