SELECT 
DATEPART(YEAR,[DTime])  AS [Год],
DATEPART(MONTH,[DTime]) AS [Месяц],
DATEPART(DAY,[DTime])   AS [День],
DATEPART(HOUR,[DTime])  AS [Час],
Round(Avg([T1]),0)      AS [V1]
FROM [XControl].[dbo].[TableX]
GROUP BY DATEPART(YEAR,[DTime]), DATEPART(MONTH,[DTime]),
	 DATEPART(DAY,[DTime]),  DATEPART(HOUR,[DTime])
ORDER BY DATEPART(YEAR,[DTime]), DATEPART(MONTH,[DTime]),
	 DATEPART(DAY,[DTime]),  DATEPART(HOUR,[DTime])

qry1.SQL.Clear;
qry1.SQL.Add('SELECT');
qry1.SQL.Add('DATEPART(YEAR, [DTime]) AS [Год],');
qry1.SQL.Add('DATEPART(MONTH,[DTime]) AS [Месяц],');
qry1.SQL.Add('DATEPART(DAY,  [DTime]) AS [День],');
qry1.SQL.Add('DATEPART(HOUR, [DTime]) AS [Час],');
qry1.SQL.Add('Round(Avg([T1]),0)      AS [V1]');
qry1.SQL.Add('FROM [XControl].[dbo].[TableX]');
qry1.SQL.Add('GROUP BY DATEPART(YEAR,[DTime]), DATEPART(MONTH,[DTime]),');
qry1.SQL.Add('         DATEPART(DAY, [DTime]), DATEPART(HOUR, [DTime])');
qry1.SQL.Add('ORDER BY DATEPART(YEAR,[DTime]), DATEPART(MONTH,[DTime]),');
qry1.SQL.Add('         DATEPART(DAY, [DTime]), DATEPART(HOUR, [DTime])');
qry1.Open;

qry1.SQL.Clear;
    qry1.SQL.Add('SELECT');
    qry1.SQL.Add('[DTime],T1,[T2],[T3],[T4]');
    qry1.SQL.Add('FROM');
    qry1.SQL.Add('[XControl].[dbo].[TableX]');
    qry1.SQL.Add('WHERE [DTime] BETWEEN :dt1 AND :dt2');
    qry1.SQL.Add('ORDER BY [DTime]');
    qry1.Parameters.ParseSQL(qry1.SQL.Text, True);
    qry1.Parameters.ParamByName('dt1').Value := dtp1.DateTime;
    qry1.Parameters.ParamByName('dt2').Value := dtp2.DateTime;
    qry1.Open;