MS SQL Server - Left Join

In this article, we would like to show you how to use LEFT JOIN in MS SQL Server.

Quick solution:

SELECT [column1], [column2], [columnN]
FROM [table1]
LEFT JOIN [table2]
ON [table1].[column_name] = [table2].[column_name];

Practical example

To show how the LEFT JOIN works, we will use the following tables:

Note:

At the end of this article you can find databases preparation SQL queries.

Example 

In this example, we will select all users with department information.

Query:

SELECT * FROM [users]
LEFT JOIN [departments] 
ON [departments].[id] = [users].[department_id];

Output:

Database preparation

create_tables.sql file:

CREATE TABLE [departments] (
	[id] INT NOT NULL,
	[department_name] VARCHAR(50) NOT NULL,
	[location] VARCHAR(50) NULL,
	PRIMARY KEY ([id])
);

CREATE TABLE [users] (
	[id] INT IDENTITY(1,1),
	[name] VARCHAR(50) NOT NULL,
	[surname] VARCHAR(50) NOT NULL,
	[department_id] INT,
	PRIMARY KEY ([id]),
	FOREIGN KEY ([department_id]) REFERENCES [departments] ([id])
);

insert_data.sql file:

INSERT INTO [departments]
	([id], [department_name], [location])
VALUES
	(1, 'Sales', 'New York'),
	(2, 'Finance', NULL),
	(3, 'HR', 'Atlanta'),
	(4, 'Purchase', 'New Orlean'),
	(5, 'Operations', 'Boston');

INSERT INTO [users]
	( [name], [surname], [department_id])
VALUES
	('John', 'Stewart', 1),
	('Chris', 'Brown', 2),
	('Kate', 'Lewis', 3),
	('Ailisa', 'Gomez', NULL),
	('Gwendolyn', 'James', 2),
	('Simon', 'Collins', 4),
	('Taylor', 'Martin', 2),
	('Andrew', 'Thompson', NULL);