Create rearrange-products-table.sql

Author: kamyu104

MySQL/rearrange-products-table.sql

@@ -0,0 +1,20 @@
+# Time:  O(n)
+# Space: O(n)
+
+SELECT product_id,
+       'store1' AS store,
+       store1   AS price
+FROM   products
+WHERE  store1 IS NOT NULL
+UNION ALL
+SELECT product_id,
+       'store2' AS store,
+       store2   AS price
+FROM   products
+WHERE  store2 IS NOT NULL
+UNION ALL
+SELECT product_id,
+       'store3' AS store,
+       store3   AS price
+FROM   products
+WHERE  store3 IS NOT NULL;