Create number-of-accounts-that-did-not-stream.sql

Author: kamyu104

MySQL/number-of-accounts-that-did-not-stream.sql

@@ -0,0 +1,20 @@
+# Time:  O(m + n)
+# Space: O(m + n)
+
+WITH bought_cte AS
+(
+    SELECT account_id
+    FROM Subscriptions
+    WHERE end_date >= '2021-01-01'
+),
+no_stream_cte AS
+(
+    SELECT account_id
+    FROM Streams
+    WHERE stream_date < '2021-01-01'
+)
+
+SELECT COUNT(a.account_id) AS accounts_count
+FROM bought_cte a
+INNER JOIN no_stream_cte b
+ON a.account_id = b.account_id;