SQL Fundamentals: Master the Basics of Data Manipulation and Retrieval

Question 1

Which of the following is not a data type supported in SQL?

Accepted Answer

Array

Answer

Integer (INT)

Answer

Variable-length character string (VARCHAR)

Answer

Boolean value (BOOLEAN)

Question 2

Which SQL statement is used to create a new table?

Accepted Answer

CREATE TABLE

Answer

ALTER TABLE

Answer

INSERT INTO

Answer

SELECT

Question 3

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

Accepted Answer

SELECT

Answer

INSERT

Answer

UPDATE

Answer

DELETE

Question 4

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

Accepted Answer

DELETE

Answer

TRUNCATE

Answer

DROP

Answer

ALTER

Question 5

Which of the following data types is NOT supported in SQL?

Accepted Answer

Array

Answer

Integer

Answer

Character

Answer

Boolean

Question 6

What is the primary purpose of the 'CREATE TABLE' statement in SQL?

Accepted Answer

To define a new table and specify its structure.

Answer

To insert data into an existing table.

Answer

To update data in an existing table.

Answer

To delete data from an existing table.

Question 7

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

Accepted Answer

Equal (=)

Answer

Addition (+)

Answer

Multiplication (*)

Answer

Modulus (%)

Question 8

Which of the following SQL commands is used to add a new row to a table?

Accepted Answer

INSERT

Answer

UPDATE

Answer

DELETE

Answer

CREATE

Question 9

Which of the following SQL functions is used to combine multiple text strings?

Accepted Answer

CONCAT

Answer

JOIN

Answer

LENGTH

Answer

SUBSTR

Question 10

Which SQL command is used to create a new table with a specified structure and data types?

Accepted Answer

CREATE TABLE

Answer

INSERT INTO

Answer

SELECT * FROM

Answer

UPDATE

Question 11

Which SQL data type is specifically designed to store dates and times, including information such as year, month, day, hour, minute, and second?

Accepted Answer

DATETIME

Answer

INT

Answer

VARCHAR

Answer

BOOLEAN

Question 12

Which SQL command is used to retrieve specific data from a table based on specified conditions?

Accepted Answer

SELECT

Answer

CREATE

Answer

INSERT

Answer

DELETE

Question 13

In an SQL WHERE clause, which logical operator is used to combine multiple conditions and evaluate them as a single expression?

Accepted Answer

OR

Answer

&

Answer

|

Answer

+

Question 14

Which SQL command is used to modify existing data within a table by updating specific columns or rows?

Accepted Answer

UPDATE

Answer

ALTER

Answer

INSERT

Answer

DELETE

Question 15

In database design, what is the primary purpose of defining a primary key for a table?

Accepted Answer

To uniquely identify each row in the table

Answer

To store the most critical data in the table

Answer

To enforce data integrity and prevent duplicate entries

Answer

To improve the performance of data retrieval queries

Question 16

Which SQL function is specifically used to determine the maximum value within a specified column of a table?

Accepted Answer

MAX()

Answer

MIN()

Answer

SUM()

Answer

COUNT()

Question 17

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

Accepted Answer

INNER JOINs only include rows that have matching values in both tables, while OUTER JOINs include all rows from one or both tables regardless of matching values.

Answer

OUTER JOINs only include rows that have matching values in both tables, while INNER JOINs include all rows from one or both tables regardless of matching values.

Answer

INNER JOINs are more efficient than OUTER JOINs.

Answer

OUTER JOINs are more commonly used than INNER JOINs.

Question 18

What is the primary purpose of creating an index on a table in SQL?

Accepted Answer

To significantly improve the speed of data retrieval queries

Answer

To ensure data integrity and prevent data corruption

Answer

To reduce the storage space required for the table

Answer

To create a backup of the table data

Question 19

Which of the following is the correct syntax for creating a table in SQL?

Accepted Answer

CREATE TABLE table_name (column1 data_type, column2 data_type, ...)

Answer

TABLE table_name (column1 data_type, column2 data_type, ...)

Answer

CREATE table table_name (column1 data_type, column2 data_type, ...)

Answer

table table_name (column1 data_type, column2 data_type, ...)

Question 20

What is the result of the following SQL query: SELECT * FROM table_name WHERE column_name = 'value';

Accepted Answer

Returns all rows from the table with the specified value in the specified column

Answer

Returns the first row from the table with the specified value in the specified column

Answer

Returns the number of rows in the table with the specified value in the specified column

Answer

Returns the distinct values of the specified column

Question 21

What is the purpose of the JOIN clause in SQL?

Accepted Answer

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

Answer

To group rows based on a specified column

Answer

To update data in multiple tables simultaneously

Answer

To delete rows from multiple tables simultaneously

Question 22

What is the result of the following SQL statement: UPDATE table_name SET column_name = 'new_value' WHERE condition;

Accepted Answer

Updates all rows in the table with the specified value in the specified column

Answer

Updates the first row in the table with the specified value in the specified column

Answer

Creates a new row in the table with the specified value in the specified column

Answer

Deletes all rows in the table with the specified value in the specified column

Question 23

What is the purpose of the FOREIGN KEY constraint?

Accepted Answer

To define a relationship between two tables

Answer

To ensure that each row has a unique value for the specified column

Answer

To prevent null values from being inserted in a specified column

Answer

To group rows based on a specified column

Question 24

Which of the following scenarios demonstrates a suitable use case for a nested subquery in SQL?

Accepted Answer

Identifying the top 10 customers with the highest total sales

Answer

Creating a new table in the database

Answer

Updating column values based on a given condition

Answer

Inserting multiple rows of data into a table

Question 25

In SQL, which clause is primarily used to group data and summarize it?

Accepted Answer

GROUP BY

Answer

SELECT

Answer

WHERE

Answer

ORDER BY

Question 26

Which of the following is NOT a built-in data type in SQL?

Accepted Answer

ARRAY

Answer

INTEGER

Answer

VARCHAR

Answer

BOOLEAN

Question 27

Which command is used to create a new database table?

Accepted Answer

CREATE TABLE

Answer

INSERT INTO

Answer

SELECT *

Answer

UPDATE

Question 28

Which clause in a SELECT statement specifies the conditions for filtering the rows to be returned?

Accepted Answer

WHERE

Answer

FROM

Answer

GROUP BY

Answer

ORDER BY

Question 29

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

Accepted Answer

To uniquely identify each row of data

Answer

To enforce data integrity

Answer

To speed up data retrieval

Answer

To store additional information

Question 30

Which operator in SQL is used to concatenate string values?

Accepted Answer

||

Answer

+

Answer

&

Answer

*

Question 31

What is the key difference between an INNER JOIN and an OUTER JOIN operation in SQL?

Accepted Answer

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

Answer

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

Answer

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

Answer

There is no difference between INNER JOIN and OUTER JOIN

Question 32

Which SQL function is used to determine the largest value within a set of rows?

Accepted Answer

MAX()

Answer

MIN()

Answer

AVG()

Answer

SUM()

Question 33

What is the primary use case for a subquery in SQL?

Accepted Answer

To embed one query within another

Answer

To improve query performance

Answer

To enforce data integrity

Answer

To reduce code duplication

Question 34

What is the main purpose of a transaction in SQL?

Accepted Answer

To ensure data integrity

Answer

To improve system performance

Answer

To simplify data manipulation

Answer

To control access to data

Question 35

Which of the following SQL statements is used to create a new table named 'Students' with columns for 'id' (INTEGER) and 'name' (TEXT)?

Accepted Answer

CREATE TABLE Students (id INTEGER, name TEXT);

Answer

CREATE STUDENT (id INTEGER, name TEXT);

Answer

MAKE TABLE Students (id INTEGER, name TEXT);

Answer

NEW TABLE Students (id INTEGER, name TEXT);

Question 36

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

Accepted Answer

INSERT

Answer

ADD

Answer

UPDATE

Answer

REPLACE

Question 37

Consider the following SQL statement: 'SELECT * FROM Students WHERE id = 10;'. What is its purpose?

Accepted Answer

Retrieves all rows from the Students table where the 'id' column is equal to 10.

Answer

Updates the record with id = 10 in the Students table.

Answer

Deletes the record with id = 10 from the Students table.

Answer

Inserts a new row with id = 10 into the Students table.

Question 38

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

Accepted Answer

=

Answer

==

Answer

IS

Answer

MATCH

Question 39

Consider the following SQL statement: 'UPDATE Students SET name = 'John Doe' WHERE id = 10;'. What is its effect?

Accepted Answer

Updates the 'name' column of the student with id = 10 to 'John Doe'.

Answer

Creates a new student with id = 10 and name = 'John Doe'.

Answer

Deletes the record with id = 10 from the Students table.

Answer

Inserts a new row with id = 10 and name = 'John Doe' into the Students table.

Question 40

Which SQL keyword is used to combine multiple tables based on matching values in a specified column?

Accepted Answer

JOIN

Answer

LINK

Answer

CONNECT

Answer

RELATE

Question 41

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

Accepted Answer

To limit the number of rows returned by the query.

Answer

To sort the results of the query.

Answer

To group the results of the query by a specific column.

Answer

To filter the results of the query based on a condition.

Question 42

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

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

Answer

Both primary keys and foreign keys are used to enforce data integrity, but primary keys are more important.

Answer

Primary keys and foreign keys are interchangeable and serve the same purpose.

Question 43

Which of the following is NOT a benefit of using SQL?

Accepted Answer

Data redundancy

Answer

Data independence

Answer

Data security

Answer

Data integrity

Question 44

What is the purpose of the CHECK constraint in SQL? Provide an example of its usage.

Accepted Answer

Validates if a column's value meets a specified condition.

Answer

Prevents duplicate entries in a column.

Answer

Ensures a column always has a value.

Answer

Defines the data type of a column.

Question 45

How do you create a stored procedure in SQL? Describe its advantages.

Accepted Answer

Use the CREATE PROCEDURE statement to define the stored procedure's name, parameters, and logic.

Answer

Create a temporary table to store the stored procedure's data.

Answer

Grant execution permissions on the stored procedure to specific users or roles.

Answer

Execute the stored procedure using the CALL statement.

Question 46

Which SQL statement is used to retrieve all records from the 'orders' table?

Accepted Answer

SELECT * FROM orders

Answer

FETCH orders

Answer

READ orders

Answer

GET * FROM orders

Question 47

Which SQL command is used to update the 'name' column of a customer with id '10' to 'John Doe'?

Accepted Answer

UPDATE customers SET name = 'John Doe' WHERE id = 10

Answer

CHANGE customers name = 'John Doe' WHERE id = 10

Answer

MODIFY customers SET name = 'John Doe' WHERE id = 10

Question 48

Which of the following data types is used to store dates and times with microsecond precision in SQL?

Accepted Answer

TIMESTAMP

Answer

DATE

Answer

DATETIME

Answer

TIME

Question 49

Which SQL function is used to calculate the average of values in a numeric column?

Accepted Answer

AVG

Answer

COUNT

Answer

SUM

Question 50

Which of the following is a valid DML statement?

Accepted Answer

DELETE FROM orders WHERE id = 10

Answer

DROP TABLE orders

Answer

CREATE INDEX orders_id ON orders(id)

Answer

GRANT SELECT ON orders TO user

Question 51

Which SQL keyword is used to create a view?

Accepted Answer

CREATE VIEW

Answer

CREATE INDEX

Answer

CREATE PROCEDURE

Answer

CREATE TABLE