Retrieve the data from Oracle (Superior difficult)

Question

Dear all,
I want to retrieve the data from the table (TABLE A), in TABLE A there are a field call RANGEFROM, However, the data type of it is "VARCHAR2". But in this field, it can contain numeric and date. Now, I want to select this field in it by a SQL statement. I want the SQL statement like this:
"SELECT * FROM TABLE_A WHERE (to_date(RANGEFROM, 'mm-dd-yyyy')) <= 'Now()';"
However, the result of the SQL only display in VARCHAR2 mode. That mean it can't compare the result. so What can I do?
Thanks
null

Answer 1

As long as the input literal for formatting the date is in always like 'mm/dd/yyyy' then you may explicitly select the RANGEFROM field in your select list as to_date(RANGEFROM,'mm/dd/yyyy');
eg:
SQL> select to_date('01122000','mm/dd/yyyy') RANGEFROM from dual;
RANGEFROM
12-JAN-00
Also this is now good for comparison:
SQL> select SYSDATE - to_date('01122000','mm/dd/yyyy') from dual;
SYSDATE-TO_DATE('01122000','MM/DD/YYYY')
339.67455
Also the same technique could be applied in your where condition as well.
Good luck :
(12 month wait for a response is not good)