Create change-null-values-in-a-table-to-the-previous-value.sql

kamyu104 · Aug 29, 2022 · 77991fe · 77991fe
1 parent c6a82d5
commit 77991fe
Showing 1 changed file with 15 additions and 0 deletions.
diff --git a/MySQL/change-null-values-in-a-table-to-the-previous-value.sql b/MySQL/change-null-values-in-a-table-to-the-previous-value.sql
@@ -0,0 +1,15 @@
+# Time:  O(nlogn)
+# Space: O(n)
+
+WITH rn_cte AS (
+    SELECT id, drink, ROW_NUMBER() OVER () AS rn
+    FROM CoffeeShop
+),
+group_cte AS (
+    SELECT id, drink, rn, SUM(NOT ISNULL(drink)) OVER (ORDER BY rn) AS group_id
+    FROM rn_cte
+)
+
+SELECT id, MAX(drink) OVER (PARTITION BY group_id) AS drink
+FROM group_cte
+ORDER BY rn;