column count based on a range
I have a student marks table with schema as given below:
Student
--------
SNO
Marks
I want to produce a result something as this:
MarksRange Count
---------- ------
0 10
10 2
20 43
: :
100 2
The above results shows that there are:
- 10 students who got a sc开发者_JAVA百科ore zero,
- 2 students how got a score between 1 to 10,
- 43 from 11-20
- and so on.
Could anyone please let me know how to write a query which produces this result?
try this:
DECLARE @Student table (SNO int,Marks int)
INSERT INTO @Student VALUES (1, 0)
INSERT INTO @Student VALUES (1, 3)
INSERT INTO @Student VALUES (1, 45)
INSERT INTO @Student VALUES (1, 95)
INSERT INTO @Student VALUES (1, 85)
INSERT INTO @Student VALUES (1, 97)
INSERT INTO @Student VALUES (1, 92)
DECLARE @StartNumber int
,@EndNumber int
SELECT @StartNumber=0
,@EndNumber=100
;WITH AllNumbers AS
(
SELECT @StartNumber AS Number
UNION ALL
SELECT Number+10
FROM AllNumbers
WHERE Number<@EndNumber
)
SELECT
n.number AS MarksRange,COUNT(s.SNO) AS CountOf
FROM AllNumbers n
LEFT OUTER JOIN @Student s ON s.Marks=n.Number OR (s.Marks>n.Number-10 AND s.Marks<=n.Number)
GROUP BY n.number
OUTPUT:
MarksRange CountOf
----------- -----------
0 1
10 1
20 0
30 0
40 0
50 1
60 0
70 0
80 0
90 1
100 3
if you are not on SQL Server 2005+ you need to replace the CTE with a Numbers table. and use a query like:
SELECT
n.number,COUNT(s.SNO),0 AS CountOf
FROM Numbers n
LEFT OUTER JOIN @Student s ON s.Marks=n.Number OR (s.Marks>n.Number-10 AND s.Marks<=n.Number)
WHERE n.Number>=@StartNumber AND n.Number<=@EndNumber AND CONVERT(decimal(3,1),n.Number/10)=n.Number/10.0
GROUP BY n.number
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