Finding dodgy numbers stored in an Oracle varchar field

Thu, 15 Mar 2012 04:33:17 GMT

I was recently required to process a large amount of data using Oracle - and for whatever reason - a field that was to be interpreted as a number was actually stored as a varchar. Which although not ideal, is generally fine of course until some non-numeric characters find there way into that field. When the table contains a few million records - how do you easily identify the offending records?

Below is the simple script I used...

declare
CURSOR c1 IS SELECT * FROM my_table;
n number;
BEGIN
 FOR r1 IN c1 LOOP
   begin
    n := To_Number(r1.offending_field);
   EXCEPTION
     WHEN OTHERS THEN
       dbms_output.put_line('bad='||r1.offending_field);
   END;
 END LOOP;
END;

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Finding dodgy numbers stored in an Oracle varchar field