Question

Given the following tables:

Table: STUDENTS

S_ID	NAME	AGE	CITY
1	Rahul	20	Delhi
2	Priya	22	Mumbai
3	David	21	Delhi
4	Neha	23	Bengaluru
5	Khurshid	22	Delhi

Table: GRADES

S_ID	SUBJECT	GRADE
1	Math	A
2	English	B
3	Math	C
4	English	D
5	Math	E

Write SQL queries for the following:

1. To display the number of students from each city.
2. To find the average age of all students.
3. To list the names of students and their grades.

Answer 1

1. SELECT CITY, COUNT(*) FROM STUDENTS GROUP BY CITY;
2. SELECT AVG(AGE) FROM STUDENTS;
3. SELECT S.NAME, G.GRADE FROM STUDENTS S JOIN GRADES G ON S.S _ ID = G.S _ ID;