Sports day teams are made by class and age. Group the students table by class and age together, and count each group. Three columns: the class, the age, and how many students.
The tables
students
id
name
class
age
city
1
Amy
1A
12
Leeds
2
Ben
1A
13
York
3
Cara
1B
12
NULL
4
Dan
1B
14
Leeds
5
Eva
1A
12
Hull
6
Finn
1C
13
NULL
7
Gus
1C
12
York
7 rows
scores
id
student_id
subject
score
1
1
math
92
2
1
art
78
3
2
math
65
4
2
art
88
5
3
math
74
6
4
math
55
7
4
art
90
8
5
math
81
9
5
art
NULL
10
7
math
99
10 rows
students
id
name
class
age
city
1
Amy
1A
12
Leeds
2
Ben
1A
13
York
3
Cara
1B
12
NULL
4
Dan
1B
14
Leeds
5
Eva
1A
12
Hull
6
Finn
1C
13
NULL
7
Gus
1C
12
York
7 rows
scores
id
student_id
subject
score
1
1
math
92
2
1
art
78
3
2
math
65
4
2
art
88
5
3
math
74
6
4
math
55
7
4
art
90
8
5
math
81
9
5
art
NULL
10
7
math
99
10 rows
query.sql
-- your code here: group by class, age and COUNT(*) the students
SELECT class, age
FROM students;
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Result
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