How to get the max amount per day for a month

I have a table with two columns: _{demo at db<>fiddle}

create table your_table("Date","Count")as values
 ('2022-01-13'::date,   8)
,('2022-01-18'::date,   14)
,('2022-01-25'::date,   24)
,('2022-02-08'::date,   50)
,('2022-02-15'::date,   15)
,('2022-03-01'::date,   6)
,('2022-03-09'::date,   32)
,('2022-03-15'::date,   10);

and I want to get the following result. Max amount per day for a month

I can’t group the query so that the result is months and days with the maximum count

Try using ROW_NUMBER() and CTE.

Table:

create table test_dt 
(
    dts date,
    amt int
);

Sample data:

insert into test_dt values('2025-03-14',10),('2025-03-11',20),('2025-03-13',19),('2025-03-16',80); 
insert into test_dt values('2025-02-01',10),('2025-02-03',40),('2025-02-08',15),('2025-02-04',99); 
insert into test_dt values('2025-01-17',10),('2025-01-13',60),('2025-01-11',87),('2025-01-21',16);  

Query:

with cte as 
( 
 select *,row_number() over(partition by to_char(dts,'YYYY-MM') order by amt desc) rnk  
 from test_dt 
) 
select dts,amt  
from cte c 
where rnk = 1;

Output: