Data Query Language (DQL): Master SQL Commands for Data Retrieval

Question 1

What is the main function of the ORDER BY clause in an SQL query?

Accepted Answer

To arrange the retrieved data in a specified order

Answer

To group the retrieved data by specific criteria

Answer

To limit the number of rows retrieved from a table

Answer

To specify conditions for selecting data from a table

Question 2

Which of the following is NOT a valid data type supported by SQL?

Accepted Answer

Array

Answer

Integer

Answer

String

Answer

Boolean

Question 3

What is the primary purpose of using aliases in SQL queries?

Accepted Answer

To assign temporary names to tables or columns for easier reference

Answer

To specify conditions for selecting data from a table

Answer

To sort the retrieved data in a specific order

Answer

To limit the number of rows retrieved from a table

Question 4

Which SQL statement is used to select and retrieve data from a database?

Accepted Answer

SELECT

Answer

UPDATE

Answer

INSERT

Answer

DELETE

Question 5

The WHERE clause in an SQL statement is primarily used to:

Accepted Answer

Filter the results based on specified conditions

Answer

Sort the results

Answer

Group the results

Answer

Aggregate the results

Question 6

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

Accepted Answer

=

Answer

==

Answer

!=

Answer

<

Question 7

To retrieve only unique values from a column in SQL, which keyword is used?

Accepted Answer

DISTINCT

Answer

UNIQUE

Answer

DIFFERENT

Answer

NOTNULL

Question 8

Which SQL operator is used to compare two dates?

Accepted Answer

BETWEEN

Answer

=

Answer

>

Answer

LIKE

Question 9

Which SQL command do you use to select specific data from a database?

Accepted Answer

SELECT

Answer

INSERT

Answer

UPDATE

Answer

DELETE

Question 10

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

Accepted Answer

To filter data based on specified conditions

Answer

To sort the results

Answer

To group the results

Answer

To limit the number of results returned

Question 11

How do you arrange the results of an SQL query in descending order?

Accepted Answer

ORDER BY column_name DESC

Answer

ORDER BY column_name ASC

Answer

SORT BY column_name DESC

Answer

ASCENDING BY column_name

Question 12

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

Accepted Answer

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

Answer

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

Answer

There is no real difference between a primary key and a foreign key

Answer

Both primary keys and foreign keys are used to enforce data integrity

Question 13

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

Accepted Answer

Union join

Answer

Inner join

Answer

Outer join

Answer

Cross join

Question 14

In SQL, which aggregate function calculates the average value of a numeric column?

Accepted Answer

AVG

Answer

MAX

Answer

MIN

Answer

SUM

Question 15

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

Accepted Answer

TEXT

Answer

INTEGER

Answer

VARCHAR

Answer

DATE

Question 16

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

Accepted Answer

SELECT *

Answer

INSERT

Answer

DELETE

Answer

UPDATE

Question 17

Which clause is commonly used to filter the data returned by a SELECT statement?

Accepted Answer

WHERE

Answer

ORDER BY

Answer

FROM

Answer

GROUP BY

Question 18

Which clause is used to sort the data returned by a SELECT statement in ascending or descending order?

Accepted Answer

ORDER BY

Answer

WHERE

Answer

HAVING

Answer

GROUP BY

Question 19

Which operator is commonly used to compare values in a WHERE clause?

Accepted Answer

=

Answer

<

Answer

>

Question 20

Which function can be used to count the number of rows in a table?

Accepted Answer

COUNT()

Answer

SUM()

Answer

AVG()

Answer

MAX()

Question 21

Which keyword is used to specify the columns to be retrieved in a SELECT statement?

Accepted Answer

SELECT

Answer

FROM

Answer

ORDER BY

Answer

WHERE

Question 22

Which clause is used to group data in a SELECT statement?

Accepted Answer

GROUP BY

Answer

WHERE

Answer

ORDER BY

Answer

HAVING