Merge branch 'main' of github.com:ankurbhambri/SQL-Learn

Author: ankurbhambri

Diff for: generate_series.sql

@@ -0,0 +1,47 @@
+/* 
+Input
+
+id | item | count 
+----+------+-------
+  1 | NYC  |     2
+  2 | KYC  |     1
+  3 | PYC  |     4
+
+Output
+
+id | item 
+----+------
+  1 | NYC
+  1 | NYC
+  2 | KYC
+  3 | PYC
+  3 | PYC
+  3 | PYC
+  3 | PYC
+
+*/
+
+CREATE TABLE item_counts (
+    id  INT,
+    item VARCHAR(3),
+    count INT
+);
+
+INSERT INTO item_counts (id, item, count) VALUES
+(1, 'NYC', 2),
+(2, 'KYC', 1),
+(3, 'PYC', 4);
+
+-- Recursively
+with recursive cte as (
+  select id, item, count, 1 as start
+  from item_counts
+  union all
+  select id, item, count, 1 + start
+  from cte
+  where start < count
+)
+select id, item from cte order by id;
+
+-- Using window function
+select id, item, generate_series(1, count) from item_counts;