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- The DATEDIFF function can be used to calculate the number of minutes between two times.
- The operator || concatenates the result with strings of zeroes representing hours and seconds. An example result would be '00:75:00'.
- CAST converts this string to time format (TIME).
- Internally a date or time is a numerical value, '1' corresponds to one day. The integer part represents the date and the fractional part the time.
- By default the column header is the formula used for the calculation. It is usually preferable to add an alias (Durée in this example)