This document discusses various SQL join operations - inner join, left join, right join, and full outer join. It provides the syntax for each join and explains how each join type handles matching and non-matching rows from the left and right tables. Examples are given showing how to write SQL queries using inner, left, right, and full outer joins. The document also briefly introduces the SQL UNION operator for combining result sets from multiple SELECT statements.

2. Disclaimer: This presentation is prepared by trainees of
baabtra as a part of mentoring program. This is not official
document of baabtra –Mentoring Partner
Baabtra-Mentoring Partner is the mentoring division of baabte System Technologies Pvt .
Ltd

3. Union and
joins in
mysqlShanu k k
shanukk89@gmail.com
www.facebook.com/shanunn
i
twitter.com/shanu
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9656153432

4. SQL UNION Operator:
• The UNION operator is used to combine
the result-set of two or more SELECT
statements.
• SELECT statement within the UNION
must have the same number of columns
• The columns must also have similar data
type

5. SQL UNION Syntax:
SELECT column_name(s) FROM table1
UNION
SELECT column_name(s) FROM table2;

6. Cus_id Name Contact
Name
Address City PostalCod
e
Country
1 Alfreds Futterkiste
Maria
Anders
Obere Str. 57 Berlin 12209 Germany
2
Ana Trujillo
Emparedados y
helados
Ana
Trujillo
Avda. de la
Constitución
2222
México D.F. 05021 Mexico
3
Antonio Moreno
Taquería
Antonio
Moreno
Mataderos
2312
México D.F. 05023 Mexico

7. Suppliers" table:
SupplierID SupplierName
ContactNa
me
Address City
PostalCod
e
Country
1 Exotic Liquid
Charlotte
Cooper
49
Gilbert
St.
Landona EC1 4SD UK
2 New Orleans
Shelley
Burke
.O. Box
78934
New
Orleans
70117 USA

8. SELECT City FROM Customers
UNION
SELECT City FROM Suppliers
ORDER BY City;

9. CI TY
Berlin
Mexico D.F
Mexico D.F
Landona
Neworleans

10. • SQL JOIN:
An SQL JOIN clause is used to
combine rows from two or more
tables, based on a common field
between them.

11. • INNER JOIN: Returns all rows when there is at
least one match in BOTH tables
• LEFT JOIN: Return all rows from the left table,
and the matched rows from the right table
• RIGHT JOIN: Return all rows from the right
table, and the matched rows from the left
table
• FULL JOIN: Return all rows when there is a
match in ONE of the tables

12. SQL INNER JOIN Syntax
SELECT column_name(s)
FROM table1
INNER JOIN table2
ON table1.column_name=table2.column_name;
• or:
SELECT column_name(s)
FROM table1
JOIN table2
ON table1.column_name=table2.column_name;
• INNER JOIN is the same as JOIN.

13. PK_DEPT_ID DEPT_NAME
1 ECE
2 CSE
3 IT

14. Pk_class_id Class_name Fk_dept_id
1 111 1
2 112 1
3 234 1
4 222 2

15. select dept_name ,class_name
from tbl_dept
inner join tbl_classes on
tbl_classes.fk_dept_id=tbl_dept.pk_dept
id;

16. RIGHT JOIN
The RIGHT JOIN keyword returns all rows from
the right table (table2), with the matching
rows in the left table (table1). The result is
NULL in the left side when there is no match.

17. SELECT column_name(s)
FROM table1
RIGHT JOIN table2
ON
table1.column_name=table2.column_name;

18. FULL OUTER JOIN
The FULL OUTER JOIN keyword returns
all rows from the left table (table1)
and from the right table (table2).

19. SQL FULL OUTER JOIN Syntax
SELECT column_name(s)
FROM table1
FULL OUTER JOIN table2
ON
table1.column_name=table2.column_name;

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