SQL Training 01

​SQL TRAINING QUIZ 01

By Where the Magic Begins

Multiple Choice

Which kind of database is the PostgreSQL?

• NoSQL

• RBDMS

Multiple Choice

What is the file format in what MSSQL stores the log files in use?

• TRN

• MDF

• BAK

• LDF

Multiple Select

Which statements about PRIMARY KEY are true?

• It uniquely identifies each row

• It can contain NULL values

• It can be composed of multiple columns

• It automatically creates an index

Multiple Select

Which clauses can be used to filter data in SQL?

• WHERE

• ORDER BY

• TOP

Multiple Select

Which statements about a One-to-Many relationship are true?

• The parent table contains the foreign key

• The child table contains the foreign key

• One record in the parent table can relate to multiple records in the child table

• It requires a link table

Multiple Select

Which statements about Many-to-Many relationships are correct?

• Requires a link table

• Each table can have multiple related rows in the other table

• Not able to use constraints in their columns

Multiple Choice

Which JOIN returns all rows from both tables, including unmatched rows?

• INNER JOIN

• LEFT JOIN

• FULL OUTER JOIN

• CROSS JOIN

Multiple Select

Which JOIN types can return NULL values in the result set?

• INNER JOIN

• LEFT JOIN

• RIGHT JOIN

• FULL OUTER JOIN

• CROSS JOIN

Multiple Select

Which JOIN types can potentially increase the number of rows compared to the original tables?

• INNER JOIN

• LEFT JOIN

• FULL OUTER JOIN

• CROSS JOIN

Multiple Choice

Which of the following statements about FLOAT and REAL is true?

• Both are exact numeric types

• FLOAT is approximate, REAL is exact

• Both are approximate numeric types

• REAL is used for integers only

Multiple Choice

What is the difference between CHAR and VARCHAR?

• CHAR is variable-length, VARCHAR is fixed-length

• CHAR is fixed-length, VARCHAR is variable-length

• Both are fixed-length

• Both are variable-length

Multiple Select

Which of the following are deprecated in MSSQL?

• TEXT

• NTEXT

• IMAGE

• NVARCHAR(MAX)

Multiple Select

Which data types support fractional seconds?

• DATETIME

• DATETIME2

• SMALLDATETIME

• TIME

Multiple Select

Which of the following are drawbacks of using UNIQUEIDENTIFIER as a primary key?

• Larger storage size compared to INT

• Cannot be indexed

• Fragmentation in clustered indexes

• No default function to generate one in case of insert

Multiple Select

Which clauses can be used with SELECT?

• FROM

• WHERE

• TOP

• ORDER BY

Multiple Select

Which of the following are valid ways to select all columns from a table?

• SELECT * FROM Employees

• SELECT ALL FROM Employees

• SELECT Employees.* FROM Employees

• SELECT * Employees

Multiple Select

Which of the following are valid ways to sort by multiple columns?

• ORDER BY LastName, FirstName

• ORDER BY LastName ASC, FirstName DESC

• ORDER BY 1, 2

• ORDER BY LastName AND FirstName

Multiple Choice

Which of the following is valid syntax to return the top 5 rows?

• SELECT TOP 5 * FROM Employees

• SELECT LIMIT 5 * FROM Employees

• SELECT FIRST 5 * FROM Employees

• SELECT * FROM Employees TOP 5

Fill in the Blanks

What keyword is missing f?

SELECT TOP(10) Id

Employees WHERE Id > 100

Fill in the Blanks

What keyword is wrong?

SELECT * FROM Orders ORDER BY OrderDate DESC LIMIT 1