Create find-the-subtasks-that-did-not-execute.sql

Author: kamyu104

MySQL/find-the-subtasks-that-did-not-execute.sql

@@ -0,0 +1,18 @@
+# Time:  O(n * c), c is the max of subtask count
+# Space: O(n * c)
+
+WITH RECURSIVE CTE AS
+  (SELECT 1 AS subtask_id
+   UNION ALL SELECT subtask_id + 1
+   FROM CTE
+   WHERE subtask_id <
+       (SELECT MAX(subtasks_count)
+        FROM Tasks) )
+SELECT Tasks.task_id,
+       CTE.subtask_id
+FROM CTE
+INNER JOIN Tasks ON CTE.subtask_id <= Tasks.subtasks_count
+LEFT JOIN Executed ON Tasks.task_id = Executed.task_id
+                      AND CTE.subtask_id = Executed.subtask_id
+WHERE Executed.subtask_id IS NULL
+ORDER BY NULL;