sql joins.pptx
- 2. What is SQL Join? SQL JOINS are used to retrieve data from multiple tables. A SQL JOIN is performed whenever two or more tables are listed in a SQL statement.
- 3. List of SQL JOINS ❖ INNER JOIN OUTER JOIN LEFT JOIN OR LEFT OUTER JOIN RIGHT JOIN OR RIGHT OUTER JOIN FULL JOIN OR FULL OUTER JOIN ❖ CROSS JOIN ❖ NATURAL JOIN ❖ SELF JOIN
- 4. ❖ EQUI JOIN ● EQUI JOIN is a simple SQL join. ● Uses the equal sign(=) as the comparison operator for the condition ● NON EQUI JOIN uses comparison operator other than the equal sign. ● The operators uses like >, <, >=, <= with the condition. ❖ NON EQUI JOIN
- 5. INNER JOIN ★ The INNER JOIN selects all rows from both participating tables as long as there is a match between the columns. ★ An SQL INNER JOIN is same as JOIN clause, combining rows from two or more tables.
- 6. Example : INNER JOIN Name Age Dany 20 Sam 23 Abd 21 Name Age Guna 21 Sam 23 Raj 20 cricket Football SELECT * FROM cricket INNER JOIN football ON cricket.name=football.name; Name Age Name Age Sam 23 Sam 23 Output cricket football Sam,23
- 7. LEFT JOIN or LEFT OUTER JOIN ★ The SQL LEFT JOIN, joins two tables and fetches rows based on a condition, which are matching in both the tables. ★ The unmatched rows will also be available from the table before the JOIN clause.
- 8. Example : LEFT JOIN or LEFT OUTER JOIN Name Age Dany 20 Sam 23 Abd 21 Name Age Guna 21 Sam 23 Raj 20 cricket football SELECT * FROM cricket LEFT JOIN football ON cricket.name=football.name; Name Age Name Age Dany 20 Sam 23 Sam 23 null null Abd 21 null null Output cricket football Dany Sam Abd Sam
- 9. RIGHT JOIN or RIGHT OUTER JOIN ★ The SQL RIGHT JOIN, joins two tables and fetches rows based on a condition, which are matching in both the tables. ★ The unmatched rows will also be available from the table written after the JOIN clause.
- 10. Example : RIGHT JOIN or RIGHT OUTER JOIN Name Age Dany 20 Sam 23 Abd 21 Name Age Guna 21 Sam 23 Raj 20 cricket football SELECT * FROM cricket RIGHT JOIN football ON cricket.name=football.name; Name Age Name Age sam 23 Sam 23 null null Guna 23 null null Raj 20 Output cricket football Guna Sam Raj Sam
- 11. ❖ Combines the results of both left and right outer joins. ❖ Returns all matched or unmatched rows. ❖ Includes tables on both sides of the join clause. FULL OUTER JOIN
- 12. Example : FULL OUTER JOIN Name Age Dany 20 Sam 23 Abd 21 Name Age Guna 21 Sam 23 Raj 20 cricket football SELECT * FROM cricket FULL OUTER JOIN football ON cricket.name=football.name; Output cricket football Sam Guna Raj Name Age Name Age Sam 23 Sam 23 Dany 20 null null Abd 21 null null null null Raj 20 null null Guna 21 Dany Abd
- 13. CROSS JOIN ★ The CROSS JOIN is used to generate a paired combination of each row of the first table with each row of the second table. ★ This join type is also known as cartesian join.
- 14. Example : CROSS JOIN Meals Omlet Fried Egg Sausage Meals SELECT * FROM Meals CROSS JOIN Drinks; Output Drinks Drinks Orange juice Tea Coffee Meals Drinks Omlet Orange Juice Omlet Tea Omlet Coffee Fried egg Orange Juice Fried egg Tea Fried egg Coffee Sausage Orange Juice Sausage Tea Sausage Coffee Meals Omlet Fried egg Sausage Drinks Orange juice Tea Coffee
- 15. NATURAL JOIN ★ The SQL NATURAL JOIN is a type of EQUI JOIN and is structured in such a way that, columns with same name of associate tables will appear once only. ★ The associated tables have one or more pairs of identically named columns. ★ The columns must be the same data type. ★ Don’t use ON clause in a natural join.
- 16. Example : NATURAL JOIN Name Age Dany 20 Sam 23 Abd 21 cricket SELECT * FROM cricket NATURAL JOIN football; Name Age Sam 23 Output football Name Age Guna 21 Sam 23 Raj 20 Name Age Dany 20 Sam 23 Abd 21 Name Age Guna 21 Sam 23 Raj 20
- 17. SELF JOIN ★ A SQL Self join is a mechanism of joining a table to itself. You would use a self join when you wanted to create a result set joining records in the table with some other records from the same table. ★ SELF JOIN is not different type of join ★ It can be classified under any type of join Inner Join Outer Join (Right ,Left,Full) Cross Join
- 18. Example : SELF JOIN Employee ID Name Manager ID 1 Abdulla 3 2 Pragash 1 3 Sam Null 4 Guna 2 SELECT e.Name As Employee, m.Name As Manager FROM emp_tbl e LEFT JOIN emp_tbl m ON e.ManagerID = m.EmployeeID Employee Manager Pragash Abdulla Guna Pragash Abdulla Sam Sam Null Output Emp_tbl
- 19. Thank You