Finding min é max values for each day

[Patrick EGLOFF]

Hi all, this is my first post here.

I have a table (releves) with a datetime (date) and temperature values (temp_ext) for every hour.

I would like to get the datetime for min and max temperatures for each day.

I found this query but, it gives me for each day the min/max values and date YYYY-MM-DD. I need the datetime for each min / max.

sql="select cast(date as date), min(temp_ext), max(temp_ext) from releves group by 1 order by 1"

2017-05-31 20.01 31.29
2017-06-01 12.60 39.77
2017-06-02 14.37 40.14
2017-06-03 16.21 35.20

Thanks for any help.