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SQL•SQL Tutorial

SQL LEFT JOIN

Flash cards

Review the key moves

1/4

Core idea

What is the main idea behind SQL LEFT JOIN?

Lesson checks

Practice each idea before moving on

Short Mimo-style checks built from this lesson's code, terms, and sequence.

1Quick choice

Which statement best captures the main point of this lesson?

2Fill blank

Complete the missing token from the example code.

___(s)

3Order

Put the learning moves in the order that makes the concept easiest to apply.

The LEFT JOIN and LEFT OUTER JOIN keywords are equal - the OUTER keyword is optional.

If there is no match in the right table, the result for the columns from the right table will be NULL.

The LEFT JOIN returns all rows from the left table (table1), and only the matched rows from the right table (table2).

Sql Left Join

The LEFT JOIN returns all rows from the left table (table1), and only the matched rows from the right table (table2).

If there is no match in the right table, the result for the columns from the right table will be NULL.

The LEFT JOIN and LEFT OUTER JOIN keywords are equal - the OUTER keyword is optional.

LEFT JOIN Syntax

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

Note

The syntax combines two tables based on a related column , and the ON keyword is used to specify the matching condition.

Demo Database

Below is a selection from the "Customers" table:

CustomerID	CustomerName	ContactName	Address	City	PostalCode	Country
1	Alfreds Futterkiste	Maria Anders	Obere Str. 57	Berlin	12209	Germany
2	Ana Trujillo Emparedados y helados	Ana Trujillo	Avda. de la ConstituciÃ³n 2222	MÃ©xico D.F.	05021	Mexico
3	Antonio Moreno TaquerÃa	Antonio Moreno	Mataderos 2312	MÃ©xico D.F.	05023	Mexico

And a selection from the "Orders" table:

OrderID	CustomerID	EmployeeID	OrderDate	ShipperID
10308	2	7	1996-09-18	3
10309	37	3	1996-09-19	1
10310	77	8	1996-09-20	2

Here we see that the related column between the two tables above, is the "CustomerID" column.

SQL INNER JOIN

SQL RIGHT JOIN

Loading lesson path

SQL•SQL Tutorial

SQL LEFT JOIN

Flash cards

Review the key moves

1/4

Core idea

What is the main idea behind SQL LEFT JOIN?

Lesson checks

Practice each idea before moving on

Short Mimo-style checks built from this lesson's code, terms, and sequence.

1Quick choice

Which statement best captures the main point of this lesson?

2Fill blank

Complete the missing token from the example code.

___(s)

3Order

Put the learning moves in the order that makes the concept easiest to apply.

The LEFT JOIN and LEFT OUTER JOIN keywords are equal - the OUTER keyword is optional.

If there is no match in the right table, the result for the columns from the right table will be NULL.

The LEFT JOIN returns all rows from the left table (table1), and only the matched rows from the right table (table2).

Sql Left Join

The LEFT JOIN returns all rows from the left table (table1), and only the matched rows from the right table (table2).

If there is no match in the right table, the result for the columns from the right table will be NULL.

The LEFT JOIN and LEFT OUTER JOIN keywords are equal - the OUTER keyword is optional.

LEFT JOIN Syntax

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

Note

The syntax combines two tables based on a related column , and the ON keyword is used to specify the matching condition.

Demo Database

Below is a selection from the "Customers" table:

CustomerID	CustomerName	ContactName	Address	City	PostalCode	Country
1	Alfreds Futterkiste	Maria Anders	Obere Str. 57	Berlin	12209	Germany
2	Ana Trujillo Emparedados y helados	Ana Trujillo	Avda. de la ConstituciÃ³n 2222	MÃ©xico D.F.	05021	Mexico
3	Antonio Moreno TaquerÃa	Antonio Moreno	Mataderos 2312	MÃ©xico D.F.	05023	Mexico

And a selection from the "Orders" table:

OrderID	CustomerID	EmployeeID	OrderDate	ShipperID
10308	2	7	1996-09-18	3
10309	37	3	1996-09-19	1
10310	77	8	1996-09-20	2

Here we see that the related column between the two tables above, is the "CustomerID" column.

SQL INNER JOIN

SQL RIGHT JOIN