SQL Database Management: Master Data Manipulation and Querying

Question 1

Which of the following is an invalid data type in SQL?

Accepted Answer

Array

Answer

Integer

Answer

String

Answer

Blob

Question 2

Which of the following is not a core component of SQL (Structured Query Language)?

Accepted Answer

Procedural Language

Answer

Data Definition Language (DDL)

Answer

Data Manipulation Language (DML)

Question 3

Which SQL command is used to retrieve data from a specified table?

Accepted Answer

SELECT

Answer

CREATE

Answer

INSERT

Answer

UPDATE

Question 4

What is the primary purpose of the 'WHERE' clause in a SQL query?

Accepted Answer

To filter the results based on specified conditions.

Answer

To sort the results in ascending order

Answer

To group the results by a specific column

Answer

To limit the number of results returned

Question 5

Which data type in SQL is specifically designed to store dates and times?

Accepted Answer

DATETIME

Answer

BOOLEAN

Answer

VARCHAR

Answer

INTEGER

Question 6

What is the fundamental difference between a primary key and a foreign key in SQL?

Accepted Answer

A primary key uniquely identifies each row in a table, while a foreign key references the primary key of another table.

Answer

A primary key is always an integer, while a foreign key can be of any data type.

Question 7

Which SQL command is used to create a new table?

Accepted Answer

CREATE TABLE

Answer

ALTER

Answer

SELECT

Answer

DROP

Question 8

What is the main benefit of utilizing an index in SQL?

Accepted Answer

To enhance the speed of data retrieval by organizing data in a specific order.

Answer

To prevent duplicate data from being entered into a table.

Answer

To enforce data integrity by ensuring that data meets certain criteria.

Question 9

What is the primary purpose of employing a subquery in SQL?

Accepted Answer

To embed a query within another query, enabling complex data retrieval.

Answer

To create a temporary table that can be used in various queries.

Answer

To enhance the query's performance by dividing it into smaller parts.

Question 10

Which SQL function is used to calculate the average value of a set of numeric data?

Accepted Answer

AVG

Answer

MAX

Answer

SUM

Answer

MIN

Question 11

What is the main purpose of using the 'JOIN' keyword in SQL?

Accepted Answer

To merge rows from multiple tables based on a common column, combining data from those tables.

Answer

To create a new table by combining two or more existing tables.

Answer

To filter data from a table based on a specified condition.

Question 12

Which SQL statement is used to retrieve data from a table?

Accepted Answer

SELECT

Answer

UPDATE

Answer

INSERT

Answer

DELETE

Question 13

What is the primary purpose of using the WHERE clause in an SQL statement?

Accepted Answer

To filter rows based on specified conditions.

Answer

To sort the results in ascending or descending order.

Answer

To group rows by common values.

Answer

To combine data from multiple tables.

Question 14

What is the purpose of the JOIN operation in SQL?

Accepted Answer

To combine data from multiple tables based on related columns.

Answer

To filter rows based on specific criteria.

Answer

To create a new table by combining two or more tables.

Question 15

Which SQL function is used to calculate the average of a set of values?

Accepted Answer

AVG

Answer

COUNT

Answer

SUM

Answer

MAX

Question 16

What is the difference between a primary key and a foreign key in an SQL database?

Accepted Answer

A primary key uniquely identifies each row in a table, while a foreign key references a primary key in another table.

Answer

A primary key is created automatically, while a foreign key must be defined manually.

Answer

A primary key is used to sort the rows in ascending order, while a foreign key is used to filter the rows.

Question 17

Which SQL statement is used to create a new database?

Accepted Answer

CREATE DATABASE

Answer

CREATE TABLE

Answer

USE DATABASE

Answer

DROP DATABASE

Question 18

What is the purpose of using the ORDER BY clause in an SQL statement?

Accepted Answer

To sort the results in a specified order based on one or more columns.

Answer

To group rows by common values.

Answer

To create a new table with the sorted results.

Answer

To filter rows based on specific criteria.

Question 19

What is the purpose of using the GROUP BY clause in an SQL statement?

Accepted Answer

To group rows by common values and perform aggregate functions on the grouped data.

Answer

To sort the results in a specified order.

Answer

To create a new table with the grouped results.

Answer

To filter rows based on specific criteria.

Question 20

Which SQL command is primarily used to retrieve data from a database?

Accepted Answer

SELECT

Answer

INSERT

Answer

UPDATE

Answer

DELETE

Question 21

Which SQL data type is specifically designed to store dates and times?

Accepted Answer

DATETIME

Answer

BOOLEAN

Answer

INTEGER

Answer

VARCHAR

Question 22

Which SQL function is used to calculate the mean (average) of a set of numeric values?

Accepted Answer

AVG()

Answer

SUM()

Answer

COUNT()

Question 23

Which SQL command is used to create a new table in a database?

Accepted Answer

CREATE TABLE

Answer

RENAME TABLE

Answer

ALTER TABLE

Answer

DROP TABLE

Question 24

In SQL, which join type is used to combine rows from two tables based on matching values in a common column?

Accepted Answer

INNER JOIN

Answer

LEFT JOIN

Answer

RIGHT JOIN

Answer

FULL JOIN

Question 25

Which SQL statement is used to modify existing data in a database?

Accepted Answer

UPDATE

Answer

DELETE

Answer

SELECT

Answer

INSERT

Question 26

In an SQL SELECT statement, which keyword is used to specify the fields or columns to be retrieved?

Accepted Answer

SELECT

Answer

ORDER BY

Answer

FROM

Answer

WHERE

Question 27

Which SQL command is used to remove data from a database?

Accepted Answer

DELETE

Answer

SELECT

Answer

INSERT

Answer

UPDATE

Question 28

What is the primary purpose of the 'SELECT' statement in SQL?

Accepted Answer

To retrieve data from a table

Answer

To insert data into a table

Answer

To create a new table

Answer

To modify data in a table

Question 29

What is the function of the 'WHERE' clause in an SQL statement?

Accepted Answer

To filter the results of a query

Answer

To specify the columns to be displayed

Answer

To group the results of a query

Answer

To sort the results of a query

Question 30

What is the main purpose of the 'JOIN' statement in SQL?

Accepted Answer

To combine rows from two or more tables based on a related column

Answer

To insert data into a table

Answer

To create a new table

Answer

To modify data in a table

Question 31

Which of the following is an example of a function in SQL?

Accepted Answer

COUNT()

Answer

WHERE

Answer

SELECT

Question 32

What is the purpose of the 'GROUP BY' statement in SQL?

Accepted Answer

To group the results of a query based on one or more columns

Answer

To specify the columns to be displayed

Answer

To filter the results of a query

Question 33

What is the primary function of the 'ORDER BY' statement in SQL?

Accepted Answer

To sort the results of a query in ascending or descending order

Answer

To combine rows from two or more tables

Answer

To group the results of a query

Answer

To filter the results of a query

Question 34

What is the primary purpose of the 'WHERE' clause in an SQL statement?

Accepted Answer

To filter rows based on a specified condition

Answer

To sort rows in ascending order

Answer

To create a new table

Answer

To group rows by a specified column

Question 35

Which of the following operators is used to compare two values for equality in SQL?

Accepted Answer

=

Answer

/

Answer

+

Answer

*

Question 36

What is the main purpose of the 'JOIN' clause in SQL?

Accepted Answer

To combine rows from multiple tables based on a common column

Answer

To insert new rows into a table

Answer

To delete rows from a table

Question 37

Which of the following is a valid SQL aggregate function?

Accepted Answer

COUNT()

Answer

SUBTRACT()

Answer

MULTIPLY()

Answer

ADD()

Question 38

What is the fundamental difference between a primary key and a foreign key in SQL?

Accepted Answer

A primary key uniquely identifies each row in a table, while a foreign key references a primary key in another table

Answer

A primary key is used to sort rows in a table, while a foreign key is used to group rows

Question 39

What is the main purpose of the 'UNION' operator in SQL?

Accepted Answer

To combine the results of two or more SELECT statements into a single result set

Answer

To remove duplicate rows from a result set

Answer

To sort the results of a SELECT statement in descending order

Question 40

Which SQL command is used to create a new table, specifying its name and column structure?

Accepted Answer

CREATE TABLE

Answer

INSERT

Answer

UPDATE

Answer

SELECT

Question 41

What is the purpose of the 'GROUP BY' clause in SQL?

Accepted Answer

To group the results of a SELECT statement by one or more columns

Answer

To filter the results of a SELECT statement based on a specified condition

Answer

To sort the results of a SELECT statement in ascending order

Question 42

Which SQL command retrieves data from a database table?

Accepted Answer

SELECT

Answer

DELETE

Answer

UPDATE

Answer

CREATE

Question 43

What is the correct syntax to select all columns from a table named 'Customers'?

Accepted Answer

SELECT * FROM Customers;

Answer

GET * FROM Customers;

Answer

SELECT ALL FROM Customers;

Answer

SELECT Customers.*;

Question 44

To retrieve data from the 'Orders' table where 'OrderDate' is after January 1st, 2023, which SQL clause would you use?

Accepted Answer

WHERE

Answer

FROM

Answer

ORDER BY

Answer

GROUP BY

Question 45

Which SQL command modifies existing data within a table?

Accepted Answer

UPDATE

Answer

MODIFY

Answer

ALTER

Answer

INSERT

Question 46

You need to calculate the average price of all products in the 'Products' table. Which SQL function would you use?

Accepted Answer

AVG()

Answer

MAX()

Answer

COUNT()

Answer

SUM()

Question 47

What is the purpose of the 'JOIN' clause in SQL?

Accepted Answer

To combine data from multiple tables based on a related column.

Answer

To create a new table.

Answer

To delete rows from a table.

Answer

To modify existing data in a table.

Question 48

To display customer names alphabetically, which SQL clause should you use?

Accepted Answer

ORDER BY

Answer

GROUP BY

Answer

SORT BY

Answer

ASCENDING

Question 49

Which SQL statement creates a new table in a database?

Accepted Answer

CREATE TABLE

Answer

DEFINE TABLE

Answer

NEW TABLE

Answer

MAKE TABLE

Question 50

What does the 'PRIMARY KEY' constraint enforce on a table column?

Accepted Answer

Uniqueness and non-null values for the column.

Answer

Data type consistency for the column.

Answer

Data integrity within a row.

Answer

Relationship between two tables.

Question 51

You need to determine the total number of orders placed in the 'Orders' table. Which SQL function would you use?

Accepted Answer

COUNT()

Answer

MAX()

Answer

AVG()

Answer

SUM()