SQL Puzzle | Ranking Puzzle – 1 | SQL Interview Question

In this puzzle you have to provide the ranking in a new column. The logic for the ranking is that whenever you have a value “Product” then you have to start the new number and all other below should follow the same rank. Please check out the sample input and the expected output.

Sample Input

ID Vals
1 Product
2 a
3 a
4 a
5 a
6 Product
7 b
8 b
9 Product
10 c

Expected Output

ID Vals x
1 Product 1
2 a 1
3 a 1
4 a 1
5 a 1
6 Product 2
7 b 2
8 b 2
9 Product 3
10 c 3

Script – DDL and INSERT Sample Data

 ```-- CREATE TABLE RankingPuzzle ( ID INT ,Vals VARCHAR(10) ) GO INSERT INTO RankingPuzzle VALUES (1,'Product'), (2,'a'), (3,'a'), (4,'a'), (5,'a'), (6,'Product'), (7,'b'), (8,'b'), (9,'Product'), (10,'c') GO SELECT * FROM RankingPuzzle a GO -- ```

SOLUTION 1

 ```-- SELECT * , ( SELECT COUNT(*) cnt FROM RankingPuzzle b WHERE B.ID <= a.Id AND b.Vals = 'Product' )x FROM RankingPuzzle a -- ```

OUTPUT – 1

 ```-- ID Vals cnt ----------- ---------- ----------- 1 Product 1 2 a 1 3 a 1 4 a 1 5 a 1 6 Product 2 7 b 2 8 b 2 9 Product 3 10 c 3 (10 rows affected) -- ```

SOLUTION 2

 ```-- SELECT *, SUM(IIF(Vals = 'Product',1,0)) OVER (ORDER BY Id) cnt FROM RankingPuzzle -- ```

OUTPUT – 2

 ```-- ID Vals cnt ----------- ---------- ----------- 1 Product 1 2 a 1 3 a 1 4 a 1 5 a 1 6 Product 2 7 b 2 8 b 2 9 Product 3 10 c 3 (10 rows affected) -- ```

Enjoy 🙂

Pawan Khowal

Pawan is a SQL Server Developer. If you need any help in writing code/puzzle or training please email at – pawankkmr”AT”gmail.com. Meanwhile please go throgh the top pages from his blog.

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