SQL Fundamentals: Master the Basics of Data Manipulation and Definition

Question 1

Which SQL statement is used to create a new table?

Accepted Answer

CREATE TABLE

Answer

ALTER TABLE

Answer

DROP TABLE

Answer

SELECT * FROM

Question 2

Which SQL statement is used to insert a new record into a table?

Accepted Answer

INSERT INTO

Answer

UPDATE

Answer

DELETE FROM

Answer

ALTER TABLE

Question 3

What is the primary purpose of a primary key in an SQL table?

Accepted Answer

To uniquely identify each record

Answer

To enforce data integrity

Answer

To improve query performance

Answer

To store additional information

Question 4

What is the difference between a clustered and a non-clustered index in SQL?

Accepted Answer

Clustered indexes store data in the same order as the table, while non-clustered indexes store data in a separate structure.

Answer

Non-clustered indexes store data in the same order as the table, while clustered indexes store data in a separate structure.

Answer

Clustered indexes are faster than non-clustered indexes.

Answer

Non-clustered indexes are faster than clustered indexes.

Question 5

What is the main purpose of a transaction in SQL?

Accepted Answer

To ensure that a set of operations is executed atomically

Answer

To improve performance

Answer

To prevent data loss

Answer

To lock data

Question 6

Which of the following is NOT a type of database normalization?

Accepted Answer

Entity-relationship modeling (ERM)

Answer

First normal form (1NF)

Answer

Second normal form (2NF)

Answer

Third normal form (3NF)

Question 7

Why are foreign key constraints primarily implemented in SQL database relationships?

Accepted Answer

To maintain data consistency and prevent anomalies

Answer

To enhance data retrieval speed

Answer

To simplify database normalization

Question 8

Which SQL query correctly uses the GROUP BY clause to calculate the total sales for each unique product category in the 'products' table?

Accepted Answer

SELECT product_category, SUM(sales) FROM products GROUP BY product_category

Answer

SELECT product_category, sales FROM products

Answer

SELECT SUM(sales) FROM products

Answer

SELECT * FROM products GROUP BY product_category

Question 9

What is the primary purpose of the 'PRIMARY KEY' constraint?

Accepted Answer

To ensure each row in a table has a unique identifier

Answer

To establish relationships between tables

Answer

To enforce data integrity by preventing duplicate values

Answer

To improve query performance by creating an index

Question 10

Which SQL operator is used to combine the results of multiple SELECT statements?

Accepted Answer

UNION

Answer

JOIN

Answer

WHERE

Answer

GROUP BY

Question 11

What is the key difference between an 'INNER JOIN' and an 'OUTER JOIN'?

Accepted Answer

An INNER JOIN returns only matching rows, while an OUTER JOIN includes all rows from one table and matching rows from the other.

Answer

An OUTER JOIN returns only matching rows, while an INNER JOIN includes all rows from one table and matching rows from the other.

Answer

An INNER JOIN includes all rows from both tables, while an OUTER JOIN returns only matching rows.

Answer

There is no difference between an INNER JOIN and an OUTER JOIN.

Question 12

Which SQL function is used to find the largest value in a set of values?

Accepted Answer

MAX()

Answer

MIN()

Answer

AVG()

Answer

SUM()

Question 13

What is the primary purpose of an SQL 'INDEX'?

Accepted Answer

To enhance query performance by allowing faster data retrieval

Answer

To maintain data integrity by ensuring data accuracy

Answer

To establish relationships between tables

Answer

To create a backup of the database table

Question 14

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

Accepted Answer

To filter the results of the query based on specified conditions

Answer

To group the results of the query

Answer

To sort the results of the query

Answer

To limit the number of rows returned by the query

Question 15

Which SQL keyword is used to create a new database?

Accepted Answer

CREATE

Answer

ALTER

Answer

DROP

Answer

GRANT

Question 16

What is the fundamental difference between a 'VIEW' and a 'TABLE' in SQL?

Accepted Answer

A VIEW is a virtual table generated dynamically from a query, while a TABLE is a permanent data storage structure.

Answer

A TABLE is a virtual table generated dynamically from a query, while a VIEW is a permanent data storage structure.

Answer

There is no difference between a VIEW and a TABLE in SQL.

Answer

A VIEW is a permanent data storage structure, while a TABLE is a virtual table generated dynamically from a query.

Question 17

To grant specific permissions to a database user on a database object, which SQL command should you use?

Accepted Answer

GRANT

Answer

REVOKE

Answer

CREATE USER

Answer

ALTER USER

Question 18

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

Accepted Answer

UPDATE

Answer

SELECT

Answer

INSERT

Answer

DELETE

Question 19

Which SQL statement is used to change the structure of an existing table?

Accepted Answer

ALTER TABLE

Answer

UPDATE TABLE

Answer

CREATE TABLE

Question 20

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

Accepted Answer

To retrieve specific data from existing database tables

Answer

To construct a new database table

Answer

To modify data within database tables

Answer

To delete data from database tables

Question 21

Which clause is utilized to filter rows in a 'SELECT' statement?

Accepted Answer

WHERE

Answer

ORDER BY

Answer

GROUP BY

Answer

HAVING

Question 22

What fundamental distinction exists between a primary key and a foreign key?

Accepted Answer

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

Answer

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

Answer

Both primary keys and foreign keys serve the same purpose of uniquely identifying rows in tables

Answer

There is no meaningful distinction between a primary key and a foreign key

Question 23

What is the main benefit of utilizing a 'JOIN' statement?

Accepted Answer

To merge rows from multiple tables based on shared columns

Answer

To create a new database table

Answer

To delete data from database tables

Answer

To modify data within database tables

Question 24

Among the different join types, which one retrieves all rows from the left table regardless of matching rows in the right table?

Accepted Answer

LEFT JOIN

Answer

INNER JOIN

Answer

RIGHT JOIN

Answer

FULL JOIN

Question 25

What is the primary function of the 'GROUP BY' clause?

Accepted Answer

To group rows based on common values in specified columns

Answer

To filter rows based on specific conditions

Answer

To sort rows based on a specified column

Answer

To combine rows from multiple tables

Question 26

Which of the following functions is designed to calculate the average value of a column?

Accepted Answer

AVG()

Answer

SUM()

Answer

COUNT()

Answer

MIN()

Question 27

What is the primary purpose of creating a 'VIEW'?

Accepted Answer

To provide a virtual representation of data from one or more tables

Answer

To generate a new table containing a subset of data from an existing table

Answer

To modify data within database tables

Answer

To delete data from database tables

Question 28

Which SQL statement is used to create a new table and specify its structure?

Accepted Answer

CREATE TABLE

Answer

INSERT INTO

Answer

SELECT * FROM

Answer

UPDATE

Question 29

Which data type in SQL is suitable for storing text data with varying lengths?

Accepted Answer

VARCHAR

Answer

INT

Answer

FLOAT

Answer

DATE

Question 30

Which operator in SQL is used to check if two values are equal?

Accepted Answer

=

Answer

>

Answer

&&

Answer

%

Question 31

Which clause in SQL is used to restrict the rows returned by a query based on a specified condition?

Accepted Answer

WHERE

Answer

ORDER BY

Answer

GROUP BY

Answer

LIMIT

Question 32

Which statement in SQL is used to insert a new row of data into an existing table?

Accepted Answer

INSERT INTO

Answer

ADD ROW

Answer

APPEND

Answer

NEW

Question 33

Which function in SQL is used to determine the highest value within a set of values?

Accepted Answer

MAX

Answer

MIN

Answer

SUM

Answer

AVG

Question 34

Which keyword in SQL is used to combine the results of multiple queries into a single result set?

Accepted Answer

UNION

Answer

JOIN

Answer

INTERSECT

Answer

EXCEPT

Question 35

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

Accepted Answer

INNER JOIN

Answer

OUTER JOIN

Answer

LEFT JOIN

Answer

RIGHT JOIN

Question 36

Which clause in SQL is used to sort the results of a query in a specified order?

Accepted Answer

ORDER BY

Answer

GROUP BY

Answer

HAVING

Answer

LIMIT

Question 37

Which statement in SQL is used to modify the structure or definition of an existing table?

Accepted Answer

ALTER TABLE

Answer

CHANGE

Answer

MODIFY

Answer

UPDATE

Question 38

Which SQL statement is used to create an index on a table?

Accepted Answer

CREATE INDEX

Answer

ALTER TABLE

Answer

ADD INDEX

Question 39

What is the purpose of the `SELECT` statement in SQL?

Accepted Answer

To retrieve data from a table

Answer

To create a new table

Answer

To modify existing data

Answer

To delete data from a table

Question 40

Which keyword is used to create a new table in SQL?

Accepted Answer

CREATE

Answer

ALTER

Answer

INSERT

Answer

UPDATE

Question 41

What is the purpose of using the `WHERE` clause in SQL?

Accepted Answer

To specify a condition for selecting data

Answer

To sort the results of a query

Answer

To group the results of a query

Answer

To limit the number of rows returned

Question 42

What is the fundamental difference between a primary key and a unique key?

Accepted Answer

A primary key uniquely identifies each row in a table and a unique key ensures uniqueness within a specific column.

Answer

A primary key permits duplicates while a unique key does not.

Answer

A primary key is automatically generated upon table creation, unlike a unique key.

Answer

A primary key applies to a single column while a unique key can span multiple columns.

Question 43

Which SQL command is used to establish a new table?

Accepted Answer

CREATE TABLE

Answer

SELECT

Answer

INSERT

Answer

ALTER TABLE

Question 44

Which of the following is a function used to aggregate data in SQL?

Accepted Answer

SUM

Answer

JOIN

Answer

ORDER BY

Answer

DISTINCT

Question 45

Which SQL statement is used to modify data in a table?

Accepted Answer

UPDATE

Answer

CREATE

Answer

INSERT

Answer

DELETE

Question 46

Which of the following is a reserved keyword in SQL?

Accepted Answer

ORDER

Answer

username

Answer

1234

Answer

MyTable

Question 47

Which data type is appropriate for storing dates?

Accepted Answer

DATE

Answer

INT

Answer

FLOAT

Answer

VARCHAR

Question 48

Which of the following operators is used for value comparison in SQL?

Accepted Answer

=

Answer

AND

Answer

NOT

Answer

+

Question 49

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

Accepted Answer

DELETE

Answer

DROP

Answer

ALTER

Answer

TRUNCATE

Question 50

In SQL, which statement is used to create a new table?

Accepted Answer

CREATE TABLE

Answer

INSERT INTO

Answer

SHOW TABLES

Question 51

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

Accepted Answer

To filter data based on a specified condition.

Answer

To group data by a specified column.

Answer

To combine data from multiple tables.

Answer

To sort the results in a specified order.

Question 52

What is the main distinction between an INNER JOIN and an OUTER JOIN in SQL?

Accepted Answer

An INNER JOIN only returns rows where the join condition is met, while an OUTER JOIN returns all rows from one table and the matching rows from the other.

Answer

An INNER JOIN returns all rows from both tables, while an OUTER JOIN returns only the rows that match the join condition.

Answer

An INNER JOIN is used to combine tables based on a common column, while an OUTER JOIN is used to combine tables based on different columns.

Question 53

In SQL, which operator is used to compare two values for equality?

Accepted Answer

=

Answer

>

Answer

!=

Answer

<

Question 54

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

Accepted Answer

To sort the result set in a specified order.

Answer

To filter the result set based on a condition.

Answer

To group the result set by a specified column.

Answer

To combine data from multiple tables.

Question 55

Which SQL function can be used to calculate the minimum value in a set of rows?

Accepted Answer

MIN()

Answer

AVG()

Answer

SUM()

Answer

MAX()

Question 56

In SQL, which statement is used to insert a new row into a table?

Accepted Answer

INSERT INTO

Answer

SELECT FROM

Answer

UPDATE

Answer

CREATE TABLE

Question 57

What is the main difference between a database and a table in SQL?

Accepted Answer

A database is a collection of tables, while a table is a collection of rows and columns within a database.

Answer

A database stores data temporarily, while a table stores data permanently.

Answer

A database is a software program, while a table is a data structure.