Oracle counts the number of data pens for each time period of the day in 15-minute bounds

Db.table Replace with its own table name, StartTime as the date field

Select COUNT (*),
(Case Floor (To_char (StartTime, ' mi '))/15)
When 0 then To_char (StartTime, ' yyyy.mm.dd hh ') | | ': 0 0:00 '
When 1 then To_char (StartTime, ' yyyy.mm.dd hh ') | | ' : 15:00 '
When 2 then To_char (StartTime, ' yyyy.mm.dd hh ') | | ' : 30:00 '
When 3 then To_char (StartTime, ' yyyy.mm.dd hh ') | | ' : 45:00 '
End) as StartTime
From db.table
GROUP BY StartTime

Oracle counts the number of data pens for each time period of the day in 15-minute bounds