I have two string fields in a vector layer, "From" and "To", with values in the format of
I would like to calculate the difference in minutes as a decimal value, in this case 1.5, in the field calculator and write it to a real field for further calculations.
As I understood so far, I have to convert my strings to QT time type by using
But now I already reached the end of my wisdom. No matter what I try, the field calculator doesn't accept any further combination of other functions (Expression is invalid).
Can anyone please tell me how to perform this calculation and receive a real field with a real minutes value, or can point me to some resources with working examples?