Update 01_SQL.md

Notebooks/Interview Questions/01_SQL.md

@@ -10,4 +10,77 @@
 1. Can we get all salesmans information where dept name is Sales?
 
 	select * from emp,dept where emp.deptno=dept.deptno and dept.deptno=30 and job = 'SALESMAN'
+1. Write query to get studentname,teachername,subjectname based on below data.
+
+```sql
+Create table dbo.student(
+Student_ID int,
+Student_Name Varchar(50),
+Class int)
+
+Create table dbo.TEACHER(
+TID int,
+Teacher_Name Varchar(50),
+)
+
+create table dbo.SUBJECT(
+Sub_Id int,
+Sub_Name Varchar(50))
+
+create table dbo.STUDENT_SUBJECT(
+Stu_Id int,
+Sub_Id int,
+Teacher_Id int)
+
+Create table dbo.Student_Marks(
+Student_ID int,
+Sub_Id int,
+Marks int,
+Class int)
+
+INSERT INTO dbo.student (Student_ID, Student_Name,Class) VALUES
+(1, 'aaa',1),
+(2, 'bbb',2);
+
+INSERT INTO dbo.TEACHER (TID, Teacher_Name) VALUES
+(1, 'hhh'),
+(2, 'gggg');
+
+INSERT INTO dbo.SUBJECT (Sub_Id, Sub_Name) VALUES
+(1, '2maths'),
+(2, 'Science');
+
+INSERT INTO STUDENT_SUBJECT (Stu_Id, Sub_id, Teacher_Id) VALUES
+(1, 1, 1),
+(2, 1, 1);
+
+INSERT INTO Student_Marks (Student_ID, Sub_Id, Marks, Class) VALUES
+(1, 1, 34, 1),
+(1, 2, 90, 1),
+(2, 1, 55, 1),
+(2, 2, 40, 1);
+```
+``` sql
+SELECT 
+    st.Student_Name,
+    T.Teacher_Name, Sb.Sub_Name, sm.Marks,
+	 CASE
+        WHEN sm.Marks >= 0  and sm.Marks < 35 THEN 'Fail'
+		WHEN sm.Marks >= 35  and sm.Marks < 50 THEN 'Just Pass'
+		WHEN sm.Marks >= 50  and sm.Marks < 60 THEN 'Second Class'
+		WHEN sm.Marks >= 60  and sm.Marks <= 100 THEN 'First Class'        
+    END AS Grade
+FROM 
+    STUDENT_SUBJECT ss
+JOIN 
+    STUDENT st ON st.Student_ID = ss.Stu_Id
+join
+	TEACHER T ON T.TID = ss.Teacher_Id
+join SUBJECT sb ON sb.Sub_Id = ss.Sub_id
+join Student_Marks sm ON sm.Sub_Id  = ss.Sub_id and sm.Student_ID  = st.Student_ID
+```
+
+
+
+2.