Filter for invalid values

Question

10.2.0.1.0
This question is related to the following post;
DISTINCT returns error on column with TO_NUMBER
Is it possible to filter for invalid values in a column if you dont know what they could be?
I tried something like this with no success;
select distinct plot_number
from (select to_number(col_3) plot_number from user_recovery_external where col_3 > 0)I then created a view with the to_number on col_3 and tried to query with the greater than zero filter but it still returned an error.
Ben

Answer 1

Thank You for the assistance here is some sample data;
External Data
Example of the sort of lines that would be causing the error, this csv file has over half a million records in it.
BUN28N06.DAT,N06,053070, 21.48, 20,R1, 13.39,  1074,H,C,1,F,E
BUN28N06.DAT,N06,053070, 21.48, 21,R1, 13.86,  1074,H,C,1,F,E
BUN28N06.DAT,N06,053070, 21.48, 22,R1, 15.01,  1074,H,C,1,F,E
BUN28N06.DAT,N06,053070, 21.48, 23,R1, 12.69,  1074,H,C,1,F,E
BUN28N06.DAT,N06,053070, 21.48, 24,R1, 15.68,  1074,H,C,1,F,E
BUN28N06.DAT,N06,053070, 21.48, 25,R1, 15.57,  1074,H,C,1,F,E
BUN28N06.DAT,N06,053070, 21.48, 26,R1, 14.55,  1074,H,C,1,F,E
BUN28N06.DAT,N06,053070, 21.48, 27,R1, 18.60,  1074,H,C,1,F,E
BUN28N06.DAT,N06,053070, 21.48, 28,R1, 17.97,  1074,H,C,1,F,E
BUNALN06(bkup).DAT,                 CORRECTION OF HASSELBLAD MEASUREMENTS                1
BUNALN06(bkup).DAT,                                                 10:50 Friday, November 24, 1989
BUNALN06(bkup).DAT,         CELLPLOT         RADIUS         HT2     COM    SCALE2     TYPE
BUNALN06(bkup).DAT,        N06,005341,    18.14,  1,O1,    22.28     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14,  2,O1,    20.00     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14,  3,R1,    15.49     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14,  4,O1,    18.76     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14,  5,R1,    17.32     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14,  6,R1,    16.99     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14,  7,R5,    18.29     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14,  8,R5,    12.65     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14,  9,O1,    22.28     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14, 10,R1,    18.05     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14, 11,R1,    19.15     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14, 12,R1,    15.99     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14, 13,R1,    17.88     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14, 14,R1,    13.39     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14, 15,R1,    13.91     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14, 16,R1,    10.59     ,       957     ,H,C,1
BUNALN06(bkup).DAT,        N06,005341,    18.14, 17,O1,    19.54     ,       957     ,H,C,1This is the external table.
CREATE TABLE USER_RECOVERY_EXTERNAL
( COL_1  VARCHAR (255 CHAR)
, COL_2 VARCHAR (255 CHAR)
, COL_3 VARCHAR (255 CHAR)
, COL_4 VARCHAR (255 CHAR)
, COL_5 VARCHAR (255 CHAR)
, COL_6 VARCHAR (255 CHAR)
, COL_7 VARCHAR (255 CHAR)
, COL_8 VARCHAR (255 CHAR)
, COL_9 VARCHAR (255 CHAR)
, COL_10 VARCHAR (255 CHAR)
, COL_11 VARCHAR (255 CHAR)
, COL_12 VARCHAR (255 CHAR)
, COL_13 VARCHAR (255 CHAR)
, COL_14 VARCHAR (255 CHAR)
, COL_15 VARCHAR (255 CHAR)
ORGANIZATION EXTERNAL
( TYPE ORACLE_LOADER
  DEFAULT DIRECTORY "UPLOAD_DIR"
  ACCESS PARAMETERS
    ( RECORDS DELIMITED BY NEWLINE
      BADFILE "UPLOAD_DIR":'user_external.bad'
      LOGFILE "UPLOAD_DIR":'user_external.log'
      FIELDS TERMINATED BY ','
      OPTIONALLY ENCLOSED BY '"' LDRTRIM
      MISSING FIELD VALUES ARE NULL
      ( COL_1
      , COL_2
      , COL_3
      , COL_4
      , COL_5
      , COL_6
      , COL_7
      , COL_8
      , COL_9
      , COL_10
      , COL_11
      , COL_12
      , COL_13
      , COL_14
      , COL_15
  LOCATION
    ( "UPLOAD_DIR":'USER_EXTERNAL.csv'
) REJECT LIMIT UNLIMITED;
{code}