Simplified Approach Using CASE
Approach\n- Start by selecting the machine_id and calculating the time taken for each process:\n  - Use a CASE statement to distinguish between \'start\' and \'
# Approach\n- Start by selecting the `machine_id` and calculating the time taken for each process:\n  - Use a `CASE` statement to distinguish between \'start\' and \'end\' activities.\n  - For \'start\' activities, multiply the `timestamp` by -1 to prepare for subtraction in the next step.\n- Sum the calculated times for each `machine_id`.\n- Divide the sum by the count of distinct `process_id` to get the average processing time.\n- Round the result to 3 decimal places using the `ROUND` function.\n- Group the results by `machine_id`.\n\n\n# Code\n```\n/* Write your T-SQL query statement below */\n\nselect machine_id, \nround(\n  sum(case when activity_type = \'start\' then timestamp*-1 \n  else timestamp end) / count(distinct process_id), 3) as processing_time \nfrom Activity\ngroup by machine_id\n\n\n\n\n```
['Database', 'MS SQL Server']