Hello,

Could someone kindly help me rewrite the correct syntax in order to use a date and text field in a case statement. However I need to find the maximum date of the date field, so am assuming that I need to to use both to_char and to_date

case when location = 'DOSPR' then Max(TO_CHAR(TO_DATE(datetime,'YY/MM/DD'),' YY/MM/DD')) else '' end as test,

Can anyone help?

Thanks
Helen

Hello,

Unfortunately, it is not clear from your post, what is the data type of the DATETIME column.

If it is CHAR/VARCHAR2 in 'YY/MM/DD' format (to which leads the usage of conversion functions), then they have no effect except eventual failure for some values representing wrong (e.g. non-existent) date.
If it is DATE, then (as TO_DATE does not support DATE parameter) DATETIME is implicitly converted to VARCHAR2 with NLS_DATE_FORMAT format mask which will lead to undeterministic behaviour with possibilty of failure when NLS_DATE_FORMAT is set to non-matched value.

In both cases (as 'YY/MM/DD' format is ordered by its DATE representation), why not simply use MAX( DATETIME )?