How to query varchar and int - sql

Question

I have this table
name | prof |grade
------------------------
yossi math 100
tami math 70
yossi phisic 100
tami phisic 100
oren math 100
oren phisic 80
dor history 70
The query should return name of student which have grade 100 in math and phisic
The correct unswer is yossi
I used the following
SELECT name FROM [dbo].[Class_grade]
where prof in ('math', 'phisic') and grade = 100
but it returns more names why?
what is the right query?
Thanks

Answer 1

select name
from Class_Grade
where grade = 100 and
prof in ('math', 'phisic')
group by name
having count(distinct prof) = 2
Group by name and filter out the rows using having. Make sure you count the distinct occurrences of prof. In this case it is 2 because you have 2 values in your in clause.

Answer 2

Earlier i misquoted the Question
You can use Group by caluse
SELECT name FROM [Class_grade]
where prof in ('math', 'phisic') and grade = 100
group by (name)
having count(1)=2
SQL FIDDLE

Answer 3

Try this
SELECT name FROM Class_grade
WHERE prof IN ('math', 'phisic') AND grade=100
GROUP BY name
HAVING COUNT(name) > 1

Answer 4

group by and make suure you get two rows
SELECT name
FROM Class_grade
WHERE prof in ('math', 'phisic') and grade = 100
GROUP BY name
HAVING count(*) = 2
http://www.sqlfiddle.com/#!3/9308c/6
EDIT
you can grab distinct grades if the same student can have more than one 100% in a subject
SELECT name
FROM (
SELECT DISTINCT name, prof, grade
FROM Class_grade
WHERE prof in ('math', 'phisic') and grade = 100
) class_grade
GROUP BY name
HAVING count(*) = 2
http://www.sqlfiddle.com/#!3/79fd0/11

Answer 5

The OP did not state a few details:
What is the primary key on the table (i.e. can multiple lines exist for the same student for the same subject)
What is the expected result when there are multiple students who match the criteria.
If we assume that one student can have multiple grades in the same subject, many of the other answers would be wrong with the HAVING COUNT(*) clauses. Mikael Eriksson's answer satisfies that assumption, and it is possibly more performant than my below solution (though functionally different a bit too):
SELECT DISTINCT name FROM [dbo].[Class_grade] cg1
WHERE EXISTS (
SELECT 1 FROM [dbo].[Class_grade] cg2
WHERE cg2.name = cg1.name
AND cg2.prof = 'math'
AND cg2.grade = 100)
AND EXISTS (
SELECT 1 FROM [dbo].[Class_grade] cg2
WHERE cg2.name = cg1.name
AND cg2.prof = 'phisic'
AND cg2.grade = 100)
AND NOT EXISTS (
SELECT 1 FROM [dbo].[Class_grade] cg2
WHERE cg2.name = cg1.name
AND cg2.prof in ('math','phisic')
AND cg2.grade < 100)
The difference in the above code is that it will only select students who have only grade = 100 for the math and phisic subjects, even if they could have more than one grade per subject. See here.

Answer 6

select Class_grade.name
from Class_grade
inner join Class_grade Class_grade2
on Class_grade.Name = Class_grade2.name
where Class_grade.Prof = 'math' and Class_grade.grade = 100
and Class_grade2.prof = 'phisic' and Class_grade2.grade = 100
group by Class_grade.Name
try not to use distinct, its a poor coding

Answer 7

Try this:
SELECT DISTINCT name FROM [dbo].[Class_grade] where prof in ('math', 'phisic') and grade = 100
This would work as well:
SELECT DISTINCT name FROM [dbo].[Class_grade] where (prof = 'math' and grade = 100) OR (prof = 'phisics' and grade = 100)