You can use group by instead of DISTINCT to do it:

Select CONVERT(VARCHAR(10), [DateAndTime], 103) as [DateAndTime]
from dbo.Prod
group by CONVERT(VARCHAR(10), [DateAndTime], 103), CAST(DateAndTime AS DATE)
order by CAST(DateAndTime AS DATE)

As other say though, this is usually better to do on frontend side of things

You need to order by the column name in the SELECT , rather than a column from one of the tables, as once you have DISTINCT you effectively have a GROUP BY on all columns. So you need to drop the table reference in the ORDER BY .

SELECT DISTINCT
  CONVERT(VARCHAR(10), p.DateAndTime, 103) as DateAndTime
FROM dbo.Prod p
ORDER BY
  DateAndTime;

Note however that this is inefficient, because you are not able to use indexes. Furthermore, DISTINCT is usually a code-smell, as it often indicates poor data.

You can group by a conversion to date instead

SELECT DISTINCT
  CONVERT(date, p.DateAndTime) as DateAndTime
FROM dbo.Prod p
ORDER BY
  DateAndTime;

Or if you use GROUP BY then you can place it in a CROSS APPLY to avoid having to specify it multiple times.

SELECT
  v.DateAndTime  
FROM dbo.Prod p
CROSS APPLY (
    SELECT CONVERT(date, p.DateAndTime) as DateAndTime
) v
GROUP BY
  v.DateAndTime
ORDER BY
  v.DateAndTime;