JOINS
IN
ORACLE DATABASE
Batch – AHD 12
LG – AEN 52/1516
Presented by Archana Subba (970316)
Arindam Sarkar (972394)
Avik Dey (972499)
Bilas Sarkar (972492)
Chandrima Mandal(970437)
Debayan Bhowmik (1004155)
Contents
Introduction
● What is Join?
● Inner Join
● Inner Join Operation
● Left Outer Join
● Right Outer Join
● Full Outer Join
● Self Join
● Cross Join
● Conclusion
● References
●
Introduction
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Oracle database is a collection of data treated as a unit.
Structured Query Language (SQL) – computer programming
language used for getting information into and out of a
database.
SQL is an ANSI (American National Standards Institute)
standard.
Joins can be used to combine tables.
What is Join?
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SQL join is an instruction to a database to combine data from
more than one table.
There are different kinds of joins, which have different rules
for the data they retrieve Inner join
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Outer join
●
Left Outer join
●
Right Outer Join
●
Full Outer Join
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Self join
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Cross join
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Inner Join
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An inner join produces a result set that is limited to the rows
where there is a match in both tables for what we're looking
for.
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Syntax for Inner Join:
SELECT column_1,column_2.......column_n
FROM Table1
INNER JOIN Table2
ON Table1.col_name=Table2.col_name
Inner Join Operation
Enroll
Student
ID
Name
ID
Code
123
124
125
126
John
Mary
Mark
Jane
123
124
124
126
DBS
PRG
DBS
PRG
Query: SELECT * FROM Student
INNER JOIN Enroll
ON Student.id = Enroll.id
ID
Name
ID
Code
123
John
123
DBS
124
Mary
124
PRG
124
Mary
124
DBS
126
Jane
126
PRG
Left Outer Join
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A left outer join, or left join, results in a set where all of the
rows from the first, or left table are preserved.
Syntax for Left Outer Join
SELECT *
FROM Table1
LEFT OUTER JOIN Table2
ON Table1.common_field = Table2.common_field
Customers
Left Outer Join
Operation
Orders
ID
Name
Age
Add
Salary
1
Ram
32
Ahd
2000
Or_id
Year
Cust_I
d
Amou
nt
102
2009
3
3000
2
Khilan
25
Delhi
1500
100
2009
3
1500
3
Shyam
23
Kota
2000
101
2011
2
1560
4
Rani
25
Mum
6500
103
2008
4
2060
Query: SELECT ID, NAME, AMOUNT,YEAR
FROM CUSTOMERS
LEFT OUTER JOIN ORDERS
ON CUSTOMERS.ID = ORDERS.CUST_ID;
Left Outer Join
Operation
(contd...)
Output Table :
ID
Name
Amount
Year
1
Ram
null
null
2
Khilan
1560
2011
3
Shyam
3000
2009
3
Shyam
1500
2009
4
Rani
2060
2008
Right Outer Join
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A right outer join, or right join, is the same as a left join, except
the roles are reversed.
Syntax for Right Outer Join:
SELECT *
FROM Table1
RIGHT OUTER JOIN Table2
ON Table1.common_field = Table2.common_field
Right Outer Join
Operation
Customers
Orders
ID
Name
Age
Add
Salary
1
Ram
32
Ahd
2000
Or_id
Year
Cust_I
d
Amou
nt
102
2009
3
3000
2
Khilan
25
Delhi
1500
100
2009
3
1500
3
Shyam
23
Kota
2000
101
2011
2
1560
4
Rani
25
Mum
6500
103
2008
4
2060
Query: SELECT ID, NAME, AMOUNT,YEAR
FROM CUSTOMERS
RIGHT OUTER JOIN ORDERS
ON CUSTOMERS.ID = ORDERS.CUST_ID;
Right Outer Join
Operation
(contd...)
Output Table :
ID
Name
Amount
Year
3
Shyam
3000
2009
3
Shyam
1500
2009
2
Khailan
1560
2011
4
Rani
2060
2008
Full Outer Join
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A full outer join, or just outer join, produces a result set with
all of the rows of both tables, regardless of whether there are
any matches.
Syntax for Full Outer Join:
SELECT *
FROM Table1
FULL OUTER JOIN Table2
ON Table1.common_field = Table2.common_field
Full Outer Join
Operation
Customers
Orders
ID
Name
Age
Add
Salary
1
Ram
32
Ahd
2000
2
Khilan
25
Delhi
1500
3
Shyam
23
Kota
2000
4
Rani
25
Mum
6500
Or_id
Year
102
2009
3
3000
100
2009
3
1500
101
2011
2
1560
103
2008
4
2060
Query: SELECT ID, NAME, AMOUNT,YEAR
FROM CUSTOMERS
FULL OUTER JOIN ORDERS
ON CUSTOMERS.ID = ORDERS.CUST_ID;
Cust_I Amou
d
nt
Full Outer Join
Operation
(contd...)
Output Table :
ID
Name
Amount
Year
1
Ram
null
null
2
Khilan
1560
2011
3
Shyam
3000
2009
3
Shyam
1500
2009
4
Rani
2060
2008
Self Join
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We can join a single table to itself. In this case, we are using the
same table twice
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Syntax for Self Join
SELECT a.column_1, b.column_2
FROM table1 a, table 1 b
WHERE a.common_field = b.common_field
Self Join Operation
gid
first_name
last_name
favorite_tool
1
Albert
Einstein
mind
2
Albert
Slater
singlet
3
Christian
Slater
spade
4
Christian
Bale
videotapes
5
Bruce
Wayne
shovel
6
Wayne
Knight
spade
Gardener's Table
Query SELECT G1.gid, G1.first_name, G1.last_name, G2.gid, G2.first_name,
G2.last_name
FROM Gardners G1, Gardners G2
WHERE G1.first_name = G2.first_name
gid
1
3
first_name last_name
Albert
Einstein
Christian
Slater
gid
2
4
first_name last_name
Albert
Slater Output Table
Christian
Bale
Cross Join
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The cross join returns a table with a potentially very large
number of rows.
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The row count of the result is equal to the number of rows in the
first table times the number of rows in the second table.
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Each row is a combination of the rows of the first and second
table.
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Syntax for Cross Join
SELECT *
FROM Table1
CROSS JOIN Table2;
Cross Join Operation
Student
ID
NAME
123
124
125
126
John
Mary
Mark
Jane
Enrollment
ID
CODE
123
124
124
126
DBS
PRG
DBS
PRG
Query - SELECT * FROM Student
CROSS JOIN Enrollment;
Output Table
ID
NAME
CODE
123
John
DBS
123
John
PRG
123
John
DBS
123
John
PRG
124
Mary
DBS
124
Mary
PRG
124
Mary
DBS
124
Mary
PRG
And so on....
Conclusion
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SQL Joins are used to combine records from two or more tables in a
database.
INNER JOIN combines column values of two tables.
FULL OUTER JOIN is a combination of Left Outer Join and Right Outer
Join.
The SELF JOIN is used to join a table to itself.
CARTESIAN or CROSS JOIN returns the Cartesian product of the sets of
records from the joined tables.
References
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www.tutorialspoint.com/sql/sql-using-joins.htmL
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http://www.sql-join.com
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http://www.w3schools.com
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The Programming Language of ORACLE by IVAN BAYROSS.
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http://www.books24x7.com
THANK YOU...