SQL Puzzle | The Distinct Sequential Unique Records with Count | Advanced SQL

In this puzzle you have to find out the sequential unique records with their count. For more details please see the sample input and expected output.

Sample Input

Id Vals
1 p
2 q
2 q
2 q
1 p
1 p
2 q

Expected Output

Id Vals Cnts
1 p 1
2 q 3
1 p 2
2 q 1

Script – DDL and INSERT Sample Data

--

CREATE TABLE SequentialUniqueNums
(
	 Id INT
	,Vals VARCHAR(10)
)
GO

INSERT INTO SequentialUniqueNums VALUES
 (1,'p')
,(2,'q')
,(2,'q')
,(2,'q')
,(1,'p')
,(1,'p')
,(2,'q')
GO

SELECT * FROM SequentialUniqueNums
GO

--

SOLUTION 1

--

SELECT Id,Vals,COUNT(b) Cnts
FROM
(
	SELECT *, ROW_NUMBER() OVER(PARTITION BY Vals ORDER BY rnk) - rnk b FROM 
	(
		SELECT *, ROW_NUMBER() OVER(ORDER BY (SELECT 1)) rnk 
		FROM SequentialUniqueNums
	)k
)z
GROUP BY Id,Vals,b
ORDER BY MIN(rnk)

--

OUTPUT – 1

--

Id          Vals       Cnts
----------- ---------- -----------
1           p          1
2           q          3
1           p          2
2           q          1

(4 rows affected)

--

Enjoy 🙂

Please add comment(s) if you have one or multiple solutions in mind. Thank You.

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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