Calculate median for each type on the hourly aggregation

Dear all, There are three columns with data: time (time scale in steps of 10 minutes) , val (amount of transactions) and type (type of automated system - 3 different types only). I need to aggregate data for each type at the hour level - and calculate median(val) for each type on the hourly aggregation. As the answer should be 3 time series of the same length. What I did: source="data.txt" | chart median(val) by type, date_hour But X-axis contains not all hours, they aggregate into "OTHER" tab. Thanks in advance for the help.