SQL Puzzle | Getting group by sum with Total Sum in a Single Query

This puzzle is really cool. You have to get group by sum with Total Sum in a Single query.

Please check out the sample input and the expected output below-

Sample Input
Sample Input

ID Val
1 10
1 NULL
2 NULL
2 100
2 200
3 200
3 100
4 156
4 255
4 244
4 NULL
4 NULL
4 345

Expected Output

ID COUNT
1 10
2 300
3 300
4 1000
SUM 1610

Rules/Restrictions

• The solution should be should use “SELECT” statement or a CTE.

Script | use below script to create table & insert some sample data

 ``` -- CREATE TABLE GroupBySumWithTotalSum ( ID INT ,VAL INT ) GO INSERT INTO GroupBySumWithTotalSum VALUES (1, 10), (1, NULL), (2, NULL), (2, 100), (2, 200), (3, 200), (3, 100), (4, 156), (4, 255), (4, 244), (4, NULL), (4, NULL), (4, 345) GO CREATE CLUSTERED INDEX Ix_ID ON GroupBySumWithTotalSum(ID) GO -- ```

Solution 1

 ``` -- SELECT ISNULL(CAST(Id AS VARCHAR(3)),'Sum') Id, SUM(Val) Val FROM GroupBySumWithTotalSum GROUP BY Id WITH ROLLUP -- ```

Solution 2

 ``` -- SELECT ISNULL(CAST(Id AS VARCHAR(3)),'Sum') Id, SUM(Val) Val FROM GroupBySumWithTotalSum GROUP BY Id WITH CUBE -- ```

Solution 3

 ``` -- SELECT CAST(Id AS VARCHAR(3)) Id, SUM(Val) Val FROM GroupBySumWithTotalSum GROUP BY Id UNION ALL SELECT 'Sum', SUM(Val) FROM GroupBySumWithTotalSum -- ```

Execution Plan / Performance Comparison

Clearly the first & second method are the best one as in the third query we are hitting the table twice and there is a conversion warning also @ the beginning of the third query.

Add a comment if you have any other or better solution in mind. I would love to learn it. We all need to learn.

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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