need output with sub query from the tables in mysql - mysql

Question

FROM THE GIVEN TABLES: Teacher And Student
teacher_ID name city fee
------------------- ------------------------
1 Jit New York 15000
2 Nilon Paris 13000
5 Pol London 11000
6 Maj Paris 14000
7 Paul Rome 13000
3 Liza Saudi 12000
----------------------------------------------------------
student_id name city rank teacher_ID
2 Nick New York 1 1
7 Brady New York 2 1
5 Gunman California 2 2
8 Juli London 3 2
4 Faral Paris 3 6
9 Goku Berlin 1 3
3 John Moscow 2 7
1 Badstar London 5
From the Given Tables I need to make a list in ascending order for the students who holds a rank less than 3 and taught either by a teacher or by own.
It's expected output is this
name city rank Teacher city
Nick New York 1 Jit New York
John Moscow 2 Paul Rome
Gunman California 2 Nilon Paris
Brady New York 2 Jit New York
Goku Berlin 1 Liza Saudi
I tried writing sql code
SELECT name,city,rank FROM Student WHERE rank < 3 ORDER BY student_ID ASC;
That code gives me first 3 columns of the expected output however I've no idea how to get the last two column of the expected output, any suggestions are welcome

Answer 1

The query...
SELECT Student.name,
Student.city,
rank,
Teacher.name as "Teacher",
Teacher.city
FROM Student
LEFT JOIN Teacher on Teacher.teacher_ID = Student.teacher_ID
WHERE rank < 3
ORDER BY student_ID ASC;
There are a few things that you should consider in the statement
When selecting the fields you want to display you need to make sure table column references are unique. As both tables have the field name and city, you should specifically reference them using the format of [table].[column name]
There are multiple ways that you can join tables. In this case, you want to use a left join because all data exists in the tables on the left side of the join, and might not exist in the table on the right side of the join.
If the student has a result of less than 3 and no teacher, the teacher name and city will appear as null. You might want to consider adding an IFNULL or similar to make these fields clear.