B.Com Computer Notes: BCA RDBMS PRACTICAL NUMBER

PRATICAL NUMBER-7

➤ Perform Different types of joins on any two tables.

Types of joins-

A. Equi Join

B. Theta Join or Non-Equi Join

C. Self Join

D. Natural Join

E. Inner join

F. Outer Join

1. Left Outer Join

2. Right Outer Join

3. Full Outer Join

G. Cross Join

We can perform these joins by given below steps-

1. Create Student and Course table to perform join operations by given below commands-

SQL>CREATE TABLE Student

(

Enroll_No int,

Student_Name varchar(20),

Course_ID int

);

Table created.

SQL>CREATE TABLE Course

(

Course_ID int,

Course_Name varchar(20),

Course_Duration varchar(20)

);

Table created.

2. Insert records in above table by given below commands-

SQL> INSERT INTO Student VALUES(101, 'Shreya', 102);

1 row created.

SQL> INSERT INTO Student VALUES(102, 'Tanu', 103);

1 row created.

SQL> INSERT INTO Student VALUES(103, 'Roshni', 100);

1 row created.

SQL> INSERT INTO Student VALUES(104, 'Manisha', 101);

1 row created.

SQL> INSERT INTO Course VALUES(101, 'BCA', 'Three Years');

1 row created.

SQL> INSERT INTO Course VALUES(103, 'BEd', 'Two Years');

1 row created.

SQL> INSERT INTO Course VALUES(108, 'BALLB', 'Five Years');

1 row created.

3. Now check the record by below select Command-

SQL>SELECT * FROM Student;

Enroll_No	Student_Name	Course_ID
101	Shreya	102
102	Tanu	103
103	Roshni	100
104	Manisha	101

SQL> SELECT * FROM Course;

Course_ID	Course_Name	Course_Duration
101	BCA	Three Years
103	BEd	Two Years
108	BALLB	Five Years

4. Now we can start to perform the join operations by below commands-

A. Equi Join-It is used to join two tables by equal to operator(=).

SQL> SELECT Enroll_No, Student_Name, Course_Name, Course_Duration FROM Student S, Course C WHERE S.Course_ID = C.Course_ID;

Enroll_No	Student_Name	Course_Name	Course_Duration
102	Tanu	BEd	Two Years
104	Manisha	BCA	Three Years

B. Non-Equi Join-It is used to join two tables by Relational Operator except equal to operator.

SQL> SELECT Enroll_No, Student_Name, Course_Name, Course_Duration FROM Student S, Course C WHERE S.Course_ID > C.Course_ID;

Enroll_No	Student_Name	Course_Name	Course_Duration
101	Shreya	BCA	Two Years
102	Tanu	BCA	Two Years

C. Self Join- It is used to join table itself by its aliases.

SQL> SELECT S1. Enroll_No, S2. Course_ID, S1.Student_Name FROM Student S1, Student S2 WHERE S1.Enroll_No=S2.Course_ID;

Enroll_No	Course_ID	Student_Name
102	102	Tanu
103	103	Roshni
101	101	Shreya

D. Natural Join- It is used to join tables by common Attribute.

SQL> SELECT * FROM Student NATURAL JOIN Course;

Course_ID	Enroll_No	Student_Name	Course_Name	Course_Duration
103	102	Tanu	BEd	Two Years
101	104	Manisha	BCA	Three Years

E. Inner Join- It is used to join tables by common values of conditional result.

SQL> SELECT * FROM Student INNER JOIN Course ON Student.Course_ID=Course.Course_ID;

Enroll_No	Student_Name	Course_ID	Course_ID	Course_Name	Course_Duration
102	Tanu	103	103	BEd	Two Years
104	Manisha	101	101	BCA	Three Years

F. Outer Join- It is used to join tables by common Attribute as well as table remaining attributes based on different outer joins. Let us Discuss all three Outer Joins by an example of each.

1. LEFT OUTER JOIN- It is used to fetch the common result of both tables as well as complete record of Left Table and null values from Right table.

SQL> SELECT * FROM Student LEFT OUTER JOIN Course ON Student.Course_ID = Course.Course_ID;

Enroll_No	Student_Name	Course_ID	Course_ID	Course_Name	Course_Duration
104	Manisha	101	101	BCA	Three Years
102	Tanu	103	103	BEd	Two Years
103	Roshni	100
101	Shreya	102

2. RIGHT OUTER JOIN- It is used to fetch the common result of both tables as well as complete record of Right Table and null values from left table.

SQL> SELECT * FROM Student RIGHT OUTER JOIN Course ON Student.Course_ID = Course.Course_ID;

Enroll_No	Student_Name	Course_ID	Course_ID	Course_Name	Course_Duration
102	Tanu	103	103	BEd	Two Years
104	Manisha	101	101	BCA	Three Years
			108	BALLB	Five Years

3. FULL OUTER JOIN- It is used to fetch the common result of both tables as well as complete record of Left Table and right table with null values from both tables.

SQL> SELECT * FROM Student FULL OUTER JOIN Course ON Student.Course_ID = Course.Course_ID;

Enroll_No	Student_Name	Course_ID	Course_ID	Course_Name	Course_Duration
104	Manisha	101	101	BCA	Three Years
102	Tanu	103	103	BEd	Two Years
103	Roshni	100
101	Shreya	102
			108	BALLB	Five Years

G. Cross Join- It is used to join tables by mapping of each row of first table to each row of second table.

SQL> SELECT * FROM Student CROSS JOIN Course;

Enroll_No	Student_Name	Course_ID	Course_ID	Course_Name	Course_Duration
101	Shreya	102	101	BCA	Three Years
102	Tanu	103	101	BCA	Three Years
103	Roshni	100	101	BCA	Three Years
104	Manisha	101	101	BCA	Three Years
101	Shreya	102	103	BEd	Two Years
102	Tanu	103	103	BEd	Two Years
103	Roshni	100	103	BEd	Two Years
104	Manisha	101	103	BEd	Two Years
101	Shreya	102	108	BALLB	Five Years
102	Tanu	103	108	BALLB	Five Years
103	Roshni	100	108	BALLB	Five Years
104	Manisha	101	108	BALLB	Five Years