Order By Datetime in SQL Server not ordering Properly -

i trying order dataset datetime in sql server. using dd/mm/yyyy format. can assume following query simplicity.

select convert(nvarchar(50), datecolumn, 103) mytable order datecolumn desc; 

but returns records sorted dd , ignores mm,yy.you can have on following data.

29/07/2015 26/09/2015 25/09/2015 25/09/2015 24/07/2015 22/09/2015 12/06/2015 01/10/2015 

what should may include mm , yy while ordering.

my guess actual query is:

select convert(nvarchar(50), datecolumn, 103) datecolumn -------------------------------------------------^ note alias here same used in order mytable order datecolumn desc; 

the order by uses column definition in select. can change name. alternatively, use qualified column name in order by:

select convert(nvarchar(50), t.datecolumn, 103) datecolumn mytable t order t.datecolumn desc;