SELECT Year([pd]) AS id,  0  AS Parent, CStr(Year([pd])) AS Name
FROM Tbl
GROUP BY Year([pd]),  0 , CStr(Year([pd]))
UNION 
SELECT Year([pd])* 100 +Month([pd]) AS id, Year([pd]) AS Parent, Format([pd], "mmmm" ) AS Name
FROM Tbl
GROUP BY Year([pd])* 100 +Month([pd]), Year([pd]), Format([pd], "mmmm" )
UNION SELECT (Year([pd])* 100 +Month([pd]))* 100 +Day([pd]) AS id, Year([pd])* 100 +Month([pd]) AS Parent, CStr(Day([pd])) AS Name
FROM Tbl
GROUP BY (Year([pd])* 100 +Month([pd]))* 100 +Day([pd]), Year([pd])* 100 +Month([pd]), CStr(Day([pd]));