Converting varchar2 to date format

Question

I've converted date formats many times, but for some reason I'm getting an invalid number error when trying to convert a varchar2 column. I've tried the to_char and to_date function and I get the same result. The column is a date and it is formatted as DD-MON-YYYY, but I want to change it to MM/DD/YYYY. My query is below:
select to_date('fccpdate','MM/DD/YYYY')
from cc_class_scmast_v
When I try to_date I get this:
Error starting at line 1 in command:
select TO_DATE('fccpdate', 'DD-MON-YYYY') from cc_class_scmast_v where fccpdate IS NOT NULL
Error report:
SQL Error: ORA-01858: a non-numeric character was found where a numeric was expected
01858. 00000 - "a non-numeric character was found where a numeric was expected"
*Cause:    The input data to be converted using a date format model was
incorrect. The input data did not contain a number where a number was
required by the format model.
*Action:   Fix the input data or the date format model to make sure the
elements match in number and type. Then retry the operation.
When I try to_char I get this:
Error starting at line 1 in command:
select TO_char('fccpdate', 'DD-MON-YYYY') from cc_class_scmast_v where fccpdate IS NOT NULL
Error report:
SQL Error: ORA-01722: invalid number
01722. 00000 - "invalid number"
*Cause:   
*Action:
I've tried removing the single quotes from my column and that doesn't make a difference. Any help is appreciated.

Answer 1

Hi,
housetiger77 wrote:
I've converted date formats many times, but for some reason I'm getting an invalid number error when trying to convert a varchar2 column. I've tried the to_char and to_date function and I get the same result. The column is a date and it is formatted as DD-MON-YYYY,If the column is a DATE, then it has the same format that all DATEs have, which is nothing like 'DD-MON-YYYY'. Formats like that only apply to strings.
Conversely, if it is formatted as 'DD-MON-YYY', then it is a string, not a DATE.
but I want to change it to MM/DD/YYYY. My query is below:
select to_date('fccpdate','MM/DD/YYYY')
from cc_class_scmast_vTO_DATE (x, 'MM/DD/YYYY') tries to convert the string x into a DATE. Let's say it starts by taking the first 2 characters of x, to get the month. The first 2 charcters of 'fccpdate' are 'fc', which is not a valid number (at least not in base 10), let alone a number between 1 and 12, so TO_DATE raises an error.
When I try to_date I get this:
Error starting at line 1 in command:
select TO_DATE('fccpdate', 'DD-MON-YYYY') from cc_class_scmast_v where fccpdate IS NOT NULL
Error report:
SQL Error: ORA-01858: a non-numeric character was found where a numeric was expected
01858. 00000 - "a non-numeric character was found where a numeric was expected"
*Cause:    The input data to be converted using a date format model was
incorrect. The input data did not contain a number where a number was
required by the format model.
*Action:   Fix the input data or the date format model to make sure the
elements match in number and type. Then retry the operation.
When I try to_char I get this:
Error starting at line 1 in command:
select TO_char('fccpdate', 'DD-MON-YYYY') from cc_class_scmast_v where fccpdate IS NOT NULL
Error report:
SQL Error: ORA-01722: invalid number
01722. 00000 - "invalid number"
*Cause:   
*Action:
I've tried removing the single quotes from my column and that doesn't make a difference. Any help is appreciated.That's a good first step. Literals are enclosed in single-quotes, identifiers (including column names) are not. 'fccpdate' is the literal 8-character string containing 'f', 'c;, another 'c', 'p', 'd', 'a', 't' and 'e'. fccpdate (without single-quotes) can be the name of a column.
If fccpdate is a string, such as '18-JUL-2012', then you can convert it to a DATE using TO_DATE.
TO_DATE (fccpdate, 'DD-MON-YYYY')If you want to display a DATE in a particular format, use
TO_CHAR ( d
        , f
        )where d is a DATE, and f is the format string. In this case, d might be the TO_DATE expression above
TO_CHAR ( TO_DATE (fccpdate, 'DD-MON-YYYY')
        , 'MM/DD/YYYY'
I hope this answers your question.
If not, post a little sample data (CREATE TABLE and INSERT statements, relevant columns only) for all tables involved, and also post the results you want from that data.
Explain, using specific examples, how you get those results from that data.
Always say which version of Oracle you're using.
See the forum FAQ {message:id=9360002}