Oracle 21c

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alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss'
create table t(dt) as 
select to_date('2022-01-01 01:02:03','yyyy-mm-dd hh24:mi:ss')  from dual union all
select to_date('2022-01-01 09:02:03','yyyy-mm-dd hh24:mi:ss')  from dual union all
select to_date('2022-01-02 01:02:03','yyyy-mm-dd hh24:mi:ss')  from dual union all
select to_date('2022-01-02 02:02:03','yyyy-mm-dd hh24:mi:ss')  from dual union all
select to_date('2022-01-02 03:02:03','yyyy-mm-dd hh24:mi:ss')  from dual;
5 rows affected

select to_char(dt,'mm/dd/yyyy'), count(*) from t group by to_char(dt,'mm/dd/yyyy');


TO_CHAR(DT,'MM/DD/YYYY')
COUNT(*)


01/01/2022
2

01/02/2022
3


select to_char(dt,'mm/dd/yyyy'), count(*) from t group by dt;


TO_CHAR(DT,'MM/DD/YYYY')
COUNT(*)


01/01/2022
1

01/01/2022
1

01/02/2022
1

01/02/2022
1

01/02/2022
1


select dt, count(*) from t group by dt;


DT
COUNT(*)


2022-01-01 01:02:03
1

2022-01-01 09:02:03
1

2022-01-02 01:02:03
1

2022-01-02 02:02:03
1

2022-01-02 03:02:03
1


select trunc(dt,'dd'), count(*) from t group by trunc(dt,'dd')


TRUNC(DT,'DD')
COUNT(*)


2022-01-01 00:00:00
2

2022-01-02 00:00:00
3

DT	COUNT(*)
2022-01-01 01:02:03	1
2022-01-01 09:02:03	1
2022-01-02 01:02:03	1
2022-01-02 02:02:03	1
2022-01-02 03:02:03	1