finish Average Time of Process per Machine

Author: babebp

SQL/SQL-50/Average_Time_of_Process_per_Machine.sql

@@ -0,0 +1,5 @@
+select a1.machine_id, round(sum(a2.timestamp - a1.timestamp) / count(a1.machine_id), 3) as processing_time
+from Activity a1
+join Activity a2
+on a1.activity_type = "start" and a2.activity_type = "end" and a1.process_id = a2.process_id and a1.machine_id = a2.machine_id
+group by a1.machine_id;