Test Your Microsoft SQL Server LEFT JOIN Knowledge with This Quiz

Progress

True / False

A LEFT JOIN returns all records from the left table and the matched records from the right table.

True False

A LEFT JOIN returns all records from the left table and the matched records from the right table. If there is no match, the result is NULL from the right table.

True / False

In a LEFT JOIN, if no match is found, the result is NULL from the right table.

True False

In a LEFT JOIN, if no match is found, the result is NULL from the right table.

True / False

LEFT JOIN can be used to find unmatched records in the right table.

True False

LEFT JOIN can be used to find unmatched records in the right table by checking for NULL values in the right table columns.

True / False

LEFT JOIN is also known as LEFT OUTER JOIN.

True False

LEFT JOIN is also known as LEFT OUTER JOIN. They are synonymous.

True / False

In a LEFT JOIN, the result set includes only the rows that have matching values in both tables.

True False

In a LEFT JOIN, the result set includes all rows from the left table and the matched rows from the right table. If there is no match, NULL values are returned from the right table.

True / False

Using LEFT JOIN, it is possible to retrieve rows from the right table even if there are no corresponding rows in the left table.

True False

Using LEFT JOIN, it is not possible to retrieve rows from the right table if there are no corresponding rows in the left table. The left table dictates the rows that appear in the result set.

True / False

The LEFT JOIN statement will return more rows than the INNER JOIN statement if there are unmatched rows in the left table.

True False

The LEFT JOIN statement will return more rows than the INNER JOIN statement if there are unmatched rows in the left table because it includes all rows from the left table regardless of matches in the right table.

True / False

In a LEFT JOIN, the result set will include NULLs in the columns of the left table if there is no match.

True False

In a LEFT JOIN, the result set will include NULLs in the columns of the right table if there is no match for a row in the left table.

True / False

Using LEFT JOIN can help identify rows in the left table that do not have corresponding rows in the right table.

True False

Using LEFT JOIN can help identify rows in the left table that do not have corresponding rows in the right table by checking for NULLs in the columns of the right table.

Q10

True / False

LEFT JOIN always returns the same number of rows as the left table.

True False

LEFT JOIN returns all rows from the left table, which may be more than or equal to the number of rows in the left table if there are matches in the right table.

Q11

True / False

LEFT JOIN will return NULL for all columns of the right table if there is no match for a row in the left table.

True False

LEFT JOIN will return NULL for all columns of the right table if there is no match for a row in the left table.

Q12

True / False

LEFT JOIN can be used to find rows in the left table that do not have corresponding rows in the right table by filtering for NULL values in the right table columns.

True False

LEFT JOIN can be used to find rows in the left table that do not have corresponding rows in the right table by filtering for NULL values in the right table columns.

Q13

True / False

The result of a LEFT JOIN will be empty if there are no matching rows in the right table.

True False

The result of a LEFT JOIN will not be empty if there are no matching rows in the right table; it will still include all rows from the left table with NULLs for columns from the right table.

Q14

True / False

In a LEFT JOIN, the result set will include rows from the left table even if there are no corresponding rows in the right table.

True False

In a LEFT JOIN, the result set will include rows from the left table even if there are no corresponding rows in the right table.

Q15

True / False

LEFT JOIN is used when we want to return all records from the right table and the matched records from the left table.

True False

LEFT JOIN is used to return all records from the left table and the matched records from the right table.

Q16

Single Choice

Which SQL statement correctly performs a LEFT JOIN between the Customers and Orders tables?

SQL Code

SELECT Customers.CustomerID, Orders.OrderID
FROM Customers
LEFT JOIN Orders
ON Customers.CustomerID = Orders.CustomerID;

SELECT Customers.CustomerID, Orders.OrderID FROM Customers LEFT JOIN Orders ON Customers.CustomerID = Orders.CustomerID; SELECT Customers.CustomerID, Orders.OrderID FROM Customers LEFT JOIN Orders WHERE Customers.CustomerID = Orders.CustomerID; SELECT Customers.CustomerID, Orders.OrderID FROM Customers LEFT JOIN Orders USING (CustomerID);SELECT Customers.CustomerID, Orders.OrderID FROM Customers LEFT JOIN Orders HAVING Customers.CustomerID = Orders.CustomerID;

The query retrieves all CustomerIDs from the Customers table and their corresponding OrderIDs from the Orders table. If a CustomerID does not have a corresponding OrderID, the OrderID will be NULL.

Q17

Single Choice

What is the result of the following query if there are no matching rows in the Orders table? SELECT Customers.CustomerID, Orders.OrderID FROM Customers LEFT JOIN Orders ON Customers.CustomerID = Orders.CustomerID;

All CustomerIDs with corresponding OrderIDs from the Orders table. Only CustomerIDs that have matching OrderIDs. All CustomerIDs with NULL for OrderIDs where there is no match.No rows will be returned.

The result will include all CustomerIDs from the Customers table with NULL for OrderIDs where there are no matching rows in the Orders table.

Q18

Single Choice

Which of the following is true about LEFT JOIN?

LEFT JOIN returns all rows from the left table and the matched rows from the right table. LEFT JOIN returns only rows that have matches in both tables. LEFT JOIN returns all rows from the right table and the matched rows from the left table.LEFT JOIN returns only unmatched rows from both tables.

LEFT JOIN returns all rows from the left table and the matched rows from the right table. If there is no match, the result is NULL from the right table.

Q19

Single Choice

What does the LEFT JOIN keyword do?

Returns only the rows that have matching values in both tables. Returns all records from the left table, and the matched records from the right table. Returns all records from the right table, and the matched records from the left table.Returns only unmatched rows from both tables.

The LEFT JOIN keyword returns all records from the left table (table1), and the matched records from the right table (table2). The result is NULL from the right side if there is no match.

Q20

Single Choice

Which JOIN clause will retrieve all rows from the Employees table and only matching rows from the Departments table?

RIGHT JOIN INNER JOIN LEFT JOINFULL JOIN

The LEFT JOIN clause retrieves all rows from the Employees table and only matching rows from the Departments table. Non-matching rows will contain NULLs in columns from the Departments table.

Q21

Single Choice

Which SQL statement correctly performs a LEFT JOIN between the Products and Categories tables?

SQL Code

SELECT Products.ProductName, Categories.CategoryName
FROM Products
LEFT JOIN Categories
ON Products.CategoryID = Categories.CategoryID;

SELECT Products.ProductName, Categories.CategoryName FROM Products LEFT JOIN Categories ON Products.CategoryID = Categories.CategoryID; SELECT Products.ProductName, Categories.CategoryName FROM Products LEFT JOIN Categories WHERE Products.CategoryID = Categories.CategoryID; SELECT Products.ProductName, Categories.CategoryName FROM Products LEFT JOIN Categories USING (CategoryID);SELECT Products.ProductName, Categories.CategoryName FROM Products LEFT JOIN Categories HAVING Products.CategoryID = Categories.CategoryID;

The query retrieves all ProductNames from the Products table and their corresponding CategoryNames from the Categories table. If a ProductName does not have a corresponding CategoryName, the CategoryName will be NULL.

Q22

Single Choice

In a LEFT JOIN, what happens to the result if there are no matching rows in the right table?

No rows will be returned. Only rows with matching values will be returned. All rows from the left table will be returned with NULLs for columns from the right table where there is no match.All rows from the right table will be returned.

In a LEFT JOIN, if there are no matching rows in the right table, the result set will include all rows from the left table with NULLs for columns from the right table.

Q23

Single Choice

Which of the following queries uses LEFT JOIN to retrieve all students and their courses?

SQL Code

SELECT Students.StudentName, Courses.CourseName
FROM Students
LEFT JOIN Courses
ON Students.CourseID = Courses.CourseID;

SELECT Students.StudentName, Courses.CourseName FROM Students LEFT JOIN Courses ON Students.CourseID = Courses.CourseID; SELECT Students.StudentName, Courses.CourseName FROM Students LEFT JOIN Courses WHERE Students.CourseID = Courses.CourseID; SELECT Students.StudentName, Courses.CourseName FROM Students LEFT JOIN Courses USING (CourseID);SELECT Students.StudentName, Courses.CourseName FROM Students LEFT JOIN Courses HAVING Students.CourseID = Courses.CourseID;

The query retrieves all StudentNames from the Students table and their corresponding CourseNames from the Courses table. If a StudentName does not have a corresponding CourseName, the CourseName will be NULL.

Q24

Single Choice

What does the following query do? SELECT A.Name, B.Age FROM TableA A LEFT JOIN TableB B ON A.ID = B.ID;

Retrieves all Names and Ages where the IDs match. Retrieves all Names from TableA and corresponding Ages from TableB, including NULLs where there are no matches. Retrieves all Ages from TableB and corresponding Names from TableA.Retrieves only matching Names and Ages from both tables.

The query retrieves all Names from TableA and their corresponding Ages from TableB. If a Name does not have a corresponding Age, the Age will be NULL.

Q25

Single Choice

Which JOIN type is most suitable for retrieving all rows from Table1 and matching rows from Table2?

INNER JOIN RIGHT JOIN LEFT JOINFULL JOIN

The LEFT JOIN type is most suitable for retrieving all rows from Table1 and matching rows from Table2. Unmatched rows in Table2 will result in NULL values for those columns.

Q26

Single Choice

What does the LEFT JOIN statement do in the following query? SELECT Employees.Name, Salaries.Amount FROM Employees LEFT JOIN Salaries ON Employees.ID = Salaries.ID;

Returns all rows from both tables where there is a match. Returns all rows from the Salaries table and matching rows from the Employees table. Returns all rows from the Employees table and matching rows from the Salaries table.Returns only unmatched rows from both tables.

The query retrieves all Names from the Employees table and their corresponding Salary Amounts from the Salaries table. If a Name does not have a corresponding Salary, the Amount will be NULL.

Q27

Single Choice

Which of the following is a correct LEFT JOIN syntax?

SQL Code

SELECT A.Col1, B.Col2
FROM TableA A
LEFT JOIN TableB B
ON A.Key = B.Key;

SELECT A.Col1, B.Col2 FROM TableA A LEFT JOIN TableB B ON A.Key = B.Key; SELECT A.Col1, B.Col2 FROM TableA A LEFT JOIN TableB B WHERE A.Key = B.Key; SELECT A.Col1, B.Col2 FROM TableA A LEFT JOIN TableB B USING (Key);SELECT A.Col1, B.Col2 FROM TableA A LEFT JOIN TableB B HAVING A.Key = B.Key;

The syntax correctly performs a LEFT JOIN between TableA and TableB on the matching Key columns.

Q28

Single Choice

How does LEFT JOIN handle non-matching rows in the right table?

Ignores non-matching rows. Includes non-matching rows with NULL values in columns from the right table. Includes non-matching rows with NULL values in columns from both tables.Only includes rows with matching values.

LEFT JOIN returns all rows from the left table and fills in NULLs for columns from the right table where there are no matching rows.

Q29

Single Choice

What will be the result of a LEFT JOIN if there are no matching rows in both tables?

No rows will be returned. All rows from the left table with NULLs for columns from the right table. All rows from both tables with NULLs for non-matching columns.Only rows with matching values will be returned.

If there are no matching rows in both tables, the result will include all rows from the left table with NULLs for columns from the right table.

Q30

Single Choice

What is the purpose of using LEFT JOIN in the following query? SELECT A.Col1, B.Col2 FROM TableA A LEFT JOIN TableB B ON A.ID = B.ID;

To return all rows from TableA and matching rows from TableB. To return only matching rows from both tables. To return all rows from both tables.To return only non-matching rows from both tables.

The purpose of using LEFT JOIN in the query is to retrieve all rows from TableA and the matching rows from TableB. If there is no match, NULL values are returned for columns from TableB.

Q31

Multiple Choice

Which of the following queries will return all employees and their department names?

SQL Code

SELECT Employees.EmployeeName, Departments.DepartmentName
FROM Employees
LEFT JOIN Departments
ON Employees.DepartmentID = Departments.DepartmentID;

SELECT Employees.EmployeeName, Departments.DepartmentName FROM Employees LEFT JOIN Departments ON Employees.DepartmentID = Departments.DepartmentID; SELECT Employees.EmployeeName, Departments.DepartmentName FROM Employees LEFT JOIN Departments WHERE Employees.DepartmentID = Departments.DepartmentID; SELECT Employees.EmployeeName, Departments.DepartmentName FROM Employees LEFT JOIN Departments USING (DepartmentID);SELECT Employees.EmployeeName, Departments.DepartmentName FROM Employees LEFT JOIN Departments HAVING Employees.DepartmentID = Departments.DepartmentID;

The query retrieves all EmployeeNames from the Employees table and their corresponding DepartmentNames from the Departments table. If an EmployeeName does not have a corresponding DepartmentName, the DepartmentName will be NULL.

Q32

Multiple Choice

Which of the following will include all products and their categories?

SQL Code

SELECT Products.ProductName, Categories.CategoryName
FROM Products
LEFT JOIN Categories
ON Products.CategoryID = Categories.CategoryID;

Q33

Multiple Choice

Identify the queries that will return all books and their authors.

SQL Code

SELECT Books.BookTitle, Authors.AuthorName
FROM Books
LEFT JOIN Authors
ON Books.AuthorID = Authors.AuthorID;

SELECT Books.BookTitle, Authors.AuthorName FROM Books LEFT JOIN Authors ON Books.AuthorID = Authors.AuthorID; SELECT Books.BookTitle, Authors.AuthorName FROM Books LEFT JOIN Authors WHERE Books.AuthorID = Authors.AuthorID; SELECT Books.BookTitle, Authors.AuthorName FROM Books LEFT JOIN Authors USING (AuthorID);SELECT Books.BookTitle, Authors.AuthorName FROM Books LEFT JOIN Authors HAVING Books.AuthorID = Authors.AuthorID;

The query retrieves all BookTitles from the Books table and their corresponding AuthorNames from the Authors table. If a BookTitle does not have a corresponding AuthorName, the AuthorName will be NULL.

Q34

Multiple Choice

Select the queries that correctly use LEFT JOIN to retrieve all students and their grades.

SQL Code

SELECT Students.StudentName, Grades.Grade
FROM Students
LEFT JOIN Grades
ON Students.StudentID = Grades.StudentID;

SELECT Students.StudentName, Grades.Grade FROM Students LEFT JOIN Grades ON Students.StudentID = Grades.StudentID; SELECT Students.StudentName, Grades.Grade FROM Students LEFT JOIN Grades WHERE Students.StudentID = Grades.StudentID; SELECT Students.StudentName, Grades.Grade FROM Students LEFT JOIN Grades USING (StudentID);SELECT Students.StudentName, Grades.Grade FROM Students LEFT JOIN Grades HAVING Students.StudentID = Grades.StudentID;

The query retrieves all StudentNames from the Students table and their corresponding Grades from the Grades table. If a StudentName does not have a corresponding Grade, the Grade will be NULL.

Q35

Multiple Choice

Which queries will retrieve all orders and their shipment details?

SQL Code

SELECT Orders.OrderID, Shipments.ShipmentDate
FROM Orders
LEFT JOIN Shipments
ON Orders.ShipmentID = Shipments.ShipmentID;

SELECT Orders.OrderID, Shipments.ShipmentDate FROM Orders LEFT JOIN Shipments ON Orders.ShipmentID = Shipments.ShipmentID; SELECT Orders.OrderID, Shipments.ShipmentDate FROM Orders LEFT JOIN Shipments WHERE Orders.ShipmentID = Shipments.ShipmentID; SELECT Orders.OrderID, Shipments.ShipmentDate FROM Orders LEFT JOIN Shipments USING (ShipmentID);SELECT Orders.OrderID, Shipments.ShipmentDate FROM Orders LEFT JOIN Shipments HAVING Orders.ShipmentID = Shipments.ShipmentID;

The query retrieves all OrderIDs from the Orders table and their corresponding ShipmentDates from the Shipments table. If an OrderID does not have a corresponding ShipmentDate, the ShipmentDate will be NULL.

Q36

Multiple Choice

What is the purpose of the LEFT JOIN clause in this query? SELECT Employees.EmployeeName, Departments.DepartmentName FROM Employees LEFT JOIN Departments ON Employees.DepartmentID = Departments.DepartmentID;

To return all rows from the Employees table and matching rows from the Departments table. To return only matching rows from both tables. To return all rows from the Departments table and matching rows from the Employees table.To return only unmatched rows from both tables.

The purpose of the LEFT JOIN clause in the query is to retrieve all EmployeeNames from the Employees table and the matching DepartmentNames from the Departments table. If an EmployeeName does not have a corresponding DepartmentName, the DepartmentName will be NULL.

Q37

Multiple Choice

What happens when there are no matching rows in the right table in a LEFT JOIN?

No rows will be returned. Only matching rows from both tables will be returned. All rows from the left table will be returned with NULLs for columns from the right table where there is no match.All rows from both tables will be returned.

When there are no matching rows in the right table in a LEFT JOIN, the result includes all rows from the left table with NULL values for columns from the right table.

Q38

Multiple Choice

Which queries use LEFT JOIN to retrieve all customers and their orders?

SQL Code

SELECT Customers.CustomerName, Orders.OrderID
FROM Customers
LEFT JOIN Orders
ON Customers.CustomerID = Orders.CustomerID;

SELECT Customers.CustomerName, Orders.OrderID FROM Customers LEFT JOIN Orders ON Customers.CustomerID = Orders.CustomerID; SELECT Customers.CustomerName, Orders.OrderID FROM Customers LEFT JOIN Orders WHERE Customers.CustomerID = Orders.CustomerID; SELECT Customers.CustomerName, Orders.OrderID FROM Customers LEFT JOIN Orders USING (CustomerID);SELECT Customers.CustomerName, Orders.OrderID FROM Customers LEFT JOIN Orders HAVING Customers.CustomerID = Orders.CustomerID;

The query retrieves all CustomerNames from the Customers table and their corresponding OrderIDs from the Orders table. If a CustomerName does not have a corresponding OrderID, the OrderID will be NULL.

Q39

Multiple Choice

Select the queries that correctly retrieve all suppliers and their products using LEFT JOIN.

SQL Code

SELECT Suppliers.SupplierName, Products.ProductName
FROM Suppliers
LEFT JOIN Products
ON Suppliers.SupplierID = Products.SupplierID;

SELECT Suppliers.SupplierName, Products.ProductName FROM Suppliers LEFT JOIN Products ON Suppliers.SupplierID = Products.SupplierID; SELECT Suppliers.SupplierName, Products.ProductName FROM Suppliers LEFT JOIN Products WHERE Suppliers.SupplierID = Products.SupplierID; SELECT Suppliers.SupplierName, Products.ProductName FROM Suppliers LEFT JOIN Products USING (SupplierID);SELECT Suppliers.SupplierName, Products.ProductName FROM Suppliers LEFT JOIN Products HAVING Suppliers.SupplierID = Products.SupplierID;

The query retrieves all SupplierNames from the Suppliers table and their corresponding ProductNames from the Products table. If a SupplierName does not have a corresponding ProductName, the ProductName will be NULL.

Q40

Multiple Choice

Which of the following queries retrieves all employees and their managers using LEFT JOIN?

SQL Code

SELECT Employees.EmployeeName, Managers.ManagerName
FROM Employees
LEFT JOIN Managers
ON Employees.ManagerID = Managers.ManagerID;

SELECT Employees.EmployeeName, Managers.ManagerName FROM Employees LEFT JOIN Managers ON Employees.ManagerID = Managers.ManagerID; SELECT Employees.EmployeeName, Managers.ManagerName FROM Employees LEFT JOIN Managers WHERE Employees.ManagerID = Managers.ManagerID; SELECT Employees.EmployeeName, Managers.ManagerName FROM Employees LEFT JOIN Managers USING (ManagerID);SELECT Employees.EmployeeName, Managers.ManagerName FROM Employees LEFT JOIN Managers HAVING Employees.ManagerID = Managers.ManagerID;

The query retrieves all EmployeeNames from the Employees table and their corresponding ManagerNames from the Managers table. If an EmployeeName does not have a corresponding ManagerName, the ManagerName will be NULL.

Q41

Multiple Choice

Identify the queries that use LEFT JOIN to retrieve all classes and their students.

SQL Code

SELECT Classes.ClassName, Students.StudentName
FROM Classes
LEFT JOIN Students
ON Classes.ClassID = Students.ClassID;

SELECT Classes.ClassName, Students.StudentName FROM Classes LEFT JOIN Students ON Classes.ClassID = Students.ClassID; SELECT Classes.ClassName, Students.StudentName FROM Classes LEFT JOIN Students WHERE Classes.ClassID = Students.ClassID; SELECT Classes.ClassName, Students.StudentName FROM Classes LEFT JOIN Students USING (ClassID);SELECT Classes.ClassName, Students.StudentName FROM Classes LEFT JOIN Students HAVING Classes.ClassID = Students.ClassID;

The query retrieves all ClassNames from the Classes table and their corresponding StudentNames from the Students table. If a ClassName does not have a corresponding StudentName, the StudentName will be NULL.

Q42

Multiple Choice

What does the following query retrieve? SELECT Customers.CustomerName, Orders.OrderDate FROM Customers LEFT JOIN Orders ON Customers.CustomerID = Orders.CustomerID;

All CustomerNames and OrderDates where there is a match. All CustomerNames from the Customers table and their OrderDates from the Orders table, including NULLs for non-matching rows. All OrderDates from the Orders table and their corresponding CustomerNames from the Customers table.Only matching CustomerNames and OrderDates from both tables.

The query retrieves all CustomerNames from the Customers table and their corresponding OrderDates from the Orders table. If a CustomerName does not have a corresponding OrderDate, the OrderDate will be NULL.

Q43

Multiple Choice

Which query correctly retrieves all customers and their addresses using LEFT JOIN?

SQL Code

SELECT Customers.CustomerName, Addresses.Address
FROM Customers
LEFT JOIN Addresses
ON Customers.AddressID = Addresses.AddressID;

SELECT Customers.CustomerName, Addresses.Address FROM Customers LEFT JOIN Addresses ON Customers.AddressID = Addresses.AddressID; SELECT Customers.CustomerName, Addresses.Address FROM Customers LEFT JOIN Addresses WHERE Customers.AddressID = Addresses.AddressID; SELECT Customers.CustomerName, Addresses.Address FROM Customers LEFT JOIN Addresses USING (AddressID);SELECT Customers.CustomerName, Addresses.Address FROM Customers LEFT JOIN Addresses HAVING Customers.AddressID = Addresses.AddressID;

The query retrieves all CustomerNames from the Customers table and their corresponding Addresses from the Addresses table. If a CustomerName does not have a corresponding Address, the Address will be NULL.

Q44

Multiple Choice

What is the result of the following query? SELECT A.Col1, B.Col2 FROM TableA A LEFT JOIN TableB B ON A.ID = B.ID;

All Col1 values from TableA and their corresponding Col2 values from TableB, including NULLs for non-matching rows. Only matching Col1 and Col2 values from both tables. All Col2 values from TableB and their corresponding Col1 values from TableA.No rows will be returned if there are no matches.

The query retrieves all Col1 values from TableA and their corresponding Col2 values from TableB. If a Col1 value does not have a corresponding Col2 value, the Col2 value will be NULL.

Q45

Multiple Choice

Which query retrieves all employees and their departments using LEFT JOIN?

SQL Code

SELECT Employees.EmployeeName, Departments.DepartmentName
FROM Employees
LEFT JOIN Departments
ON Employees.DepartmentID = Departments.DepartmentID;

Microsoft SQL Server Database Quiz Questions