Oracle Date column cleaning

Question

I have a table1(DueDate varchar2(20)). It has thousands of date data in different format with some bad data like characters.

eg.

YYYYMMDD,
MM/DD/YYY         


        

Answer 1

This answer builds on Justin Cave’s. If you create another column that is a date field you can then do something like the following:

UPDATE table1 SET DueDate2 = my_to_date(DueDate) 
   WHERE DueDate2 IS NULL AND DueDate IS NOT NULL;

You could then re-run this update after each modification of the date format in the function. You would have to stop when all the dates not converted are invalid dates (such as ‘ABCD’).