View between Line Operations

[LexityJ]

Hello friends, I have a database with data recorded every minute. I have created a view to group all the data by hours and now I want to perform some operations on it. However, I can only retrieve data in the hour group as min, max, and avg. One thing I can do is subtract the min value from the max value within the 15:00 hour group. What I want to do is to calculate the difference between the last data point and the first data point within the 15:00 hour group. Or to calculate the difference between the last data point in the 16:00 hour group and the last data point in the 15:00 hour group. In short, instead of max and min values, I want to retrieve the first and last values and calculate the difference, and if needed, calculate the difference between the last data points in different hour groups. Does anyone have knowledge about this topic?