Date issue in report definition

In the DB we are having the data for (Date) property is in different formats lets say :

1.DD/MM/YYYY

2.YYYY-MM-DD

3.YYYYMMDD

4.YYYYMMDDTHHMMSS

Now i want to sort all the data into ascending/descending order. Currently sorting is not happening properly how we can resolve this issue.

@Vimal Vijayakumar

You might have to create a custom function alias where you consider all the date formats you have and convert in into a single format and then sort on that format.