I suspect that the query that you want is:
SELECT PersonalId, Name, LastName,
Min(TmsPrick) as Mintime, Max(TmsPrick) as Maxtime,
DATEDIFF(mi, MIN(TmsPrick), MAX(TmsPrick)) AS Expr1
FROM prickTable
GROUP BY PersonalId, name, lastname, cast(TmsPrick as date)
ORDER BY PersonalId, max(TmsPrick);
This will give the the "elapsed" time on each day, because the first and last "tmsprick".