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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