SQL Learning Quizzes: Master Database Management and Manipulation

Question 1

Which of the following is the correct syntax to create a table named 'Students' with fields 'id', 'name', and 'age'?

Accepted Answer

CREATE TABLE Students (id INTEGER, name VARCHAR(255), age INTEGER)

Answer

CREATE Students (id INTEGER, name VARCHAR(255), age INTEGER)

Answer

TABLE Students (id INTEGER, name VARCHAR(255), age INTEGER)

Answer

MAKE TABLE Students (id INTEGER, name VARCHAR(255), age INTEGER)

Question 2

What is the main purpose of a stored procedure?

Accepted Answer

To group related SQL statements together for reuse

Answer

To create a new data type in SQL

Answer

To improve the performance of complex queries

Answer

To secure data access in SQL

Question 3

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

Accepted Answer

To group rows based on a specified column and perform aggregate functions

Answer

To filter rows based on a specified condition

Answer

To sort rows based on a specified column

Answer

To join two or more tables

Question 4

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

Accepted Answer

To filter the results based on a specified condition

Answer

To specify the columns to be retrieved

Answer

To sort the results

Answer

To group the results

Question 5

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

Accepted Answer

A primary key is unique for each row, while a foreign key references another table

Answer

A foreign key is unique for each row, while a primary key references another table

Answer

Both primary keys and foreign keys can be used to enforce referential integrity

Answer

They are both used to identify rows in a table

Question 6

What is the main purpose of an index in an SQL database?

Accepted Answer

To improve query performance

Answer

To enforce data integrity

Answer

To store data in a compressed format

Answer

To provide a unique identifier for each row

Question 7

Which SQL keyword is used to create a new table and define its structure?

Accepted Answer

CREATE TABLE

Answer

GENERATE

Answer

DEFINE

Answer

NEW

Question 8

What function returns the total number of rows in a table?

Accepted Answer

COUNT(*)

Answer

ROWCOUNT()

Answer

TOTAL()

Answer

SIZE()

Question 9

Which SQL operator is used to combine the results of multiple SELECT statements into a single result set?

Accepted Answer

UNION

Answer

COMBINE

Answer

MERGE

Answer

APPEND

Question 10

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

Accepted Answer

UPDATE

Answer

RENEW

Answer

ALTER

Answer

CHANGE

Question 11

What is the difference between a primary key and a candidate key in a database table?

Accepted Answer

A primary key is unique and identifies each row uniquely, while a candidate key is not necessarily unique

Answer

A candidate key is unique and identifies each row uniquely, while a primary key is not necessarily unique

Answer

A primary key can be null, while a candidate key cannot

Answer

A candidate key can be null, while a primary key cannot

Question 12

Which SQL clause is used to specify conditions for filtering the results of a SELECT statement?

Accepted Answer

WHERE

Answer

FILTER

Answer

SELECT

Answer

IF

Question 13

Which SQL keyword is used to define a set of SQL statements that can be executed as a single unit?

Accepted Answer

PROCEDURE

Answer

FUNCTION

Answer

TRIGGER

Answer

VIEW

Question 14

Which SQL command is used to establish a new database?

Accepted Answer

CREATE DATABASE

Answer

SHOW DATABASES

Answer

USE DATABASE

Answer

DROP DATABASE

Question 15

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

Accepted Answer

To retrieve data from a database table

Answer

To create a new table in the database

Answer

To insert new data into a table

Answer

To delete data from a table

Question 16

How do primary keys differ from foreign keys in SQL?

Accepted Answer

A primary key uniquely identifies a row within a table, while a foreign key establishes a link to another table.

Answer

Foreign keys uniquely identify rows in a table, whereas primary keys reference other tables' foreign keys.

Answer

Primary keys and foreign keys both serve as unique identifiers within their respective tables.

Answer

There is no distinction between primary and foreign keys in SQL.

Question 17

What is the main advantage of utilizing indexes in SQL?

Accepted Answer

Enhanced data retrieval speed

Answer

Ensuring data integrity

Answer

Preventing duplicate data

Answer

Compressing data for storage efficiency

Question 18

Which SQL command is used to establish a new table?

Accepted Answer

CREATE TABLE

Answer

ADD TABLE

Answer

NEW TABLE

Answer

MAKE TABLE

Question 19

What is the 'JOIN' operation primarily used for in SQL?

Accepted Answer

Combining rows from multiple tables based on shared attributes

Answer

Creating a new table by merging data from existing tables

Answer

Deleting rows from multiple tables based on shared attributes

Answer

Inserting data into multiple tables based on shared attributes

Question 20

What is the main purpose of a FOREIGN KEY constraint?

Accepted Answer

To ensure data integrity by referencing another table

Answer

To create a unique index on a column

Answer

To prevent duplicate values in a column

Answer

To set a default value for a column

Question 21

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

Accepted Answer

SELECT

Answer

INSERT

Answer

UPDATE

Answer

DELETE

Question 22

What is the key difference between a WHERE clause and a HAVING clause?

Accepted Answer

WHERE filters rows, while HAVING filters groups

Answer

HAVING filters rows, while WHERE filters groups

Answer

WHERE filters columns, while HAVING filters rows

Answer

HAVING filters columns, while WHERE filters groups

Question 23

What is a primary objective of creating an index in SQL?

Accepted Answer

To enhance query performance

Answer

To enforce data integrity

Answer

To create a unique constraint on a column

Answer

To store data in a sorted order

Question 24

Which join type combines rows from two or more tables if they have matching values?

Accepted Answer

INNER JOIN

Answer

LEFT JOIN

Answer

RIGHT JOIN

Answer

FULL JOIN

Question 25

What is a fundamental purpose of using a subquery in SQL?

Accepted Answer

To generate a dataset that can be utilized within another query

Answer

To create a new table

Answer

To update data in a table

Answer

To delete data from a table

Question 26

How does a view differ from a traditional table in SQL?

Accepted Answer

A view is a virtual table that is dynamically generated, while a table is a permanent data structure

Answer

A table is a virtual table that is dynamically generated, while a view is a permanent data structure

Answer

A view and a table are essentially the same thing

Answer

A view can be modified, whereas a table cannot

Question 27

Which SQL command is used to add a new column to an existing table?

Accepted Answer

ALTER TABLE

Answer

SELECT

Answer

CREATE TABLE

Question 28

In SQL, which function is used to find the highest value in a column?

Accepted Answer

MAX()

Answer

MIN()

Answer

AVG()

Question 29

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

Accepted Answer

CREATE DATABASE

Answer

MAKE DATABASE

Answer

NEW DATABASE

Answer

ADD DATABASE

Question 30

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

Accepted Answer

Retrieving data from a table

Answer

Deleting data from a table

Answer

Inserting data into a table

Answer

Updating data in a table

Question 31

What is the distinction between a 'primary key' and a 'foreign key' in SQL?

Accepted Answer

A primary key uniquely identifies a row, while a foreign key references a primary key.

Answer

A foreign key uniquely identifies a row, while a primary key references a foreign key.

Answer

A primary key is used for sorting data, while a foreign key is used for filtering.

Question 32

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

Accepted Answer

=

Answer

<

Answer

!=

Answer

>

Question 33

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

Accepted Answer

Sorting the query results

Answer

Filtering the query results

Answer

Grouping the results of the query

Answer

Limiting the number of returned results

Question 34

What is the purpose of using a 'GROUP BY' clause in an SQL query?

Accepted Answer

Grouping rows sharing similar values into summary rows.

Answer

Sorting the query results

Answer

Filtering the results of the query

Answer

Limiting the number of returned results

Question 35

Which SQL statement is used to select all rows and fields from the table 'Orders'?

Accepted Answer

SELECT * FROM Orders

Answer

GET * FROM Orders

Answer

FETCH ALL Orders

Question 36

Which SQL keyword is used to filter rows in a query based on a condition?

Accepted Answer

WHERE

Answer

IF

Answer

ELSE

Answer

THEN

Question 37

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

Accepted Answer

=

Answer

!=

Answer

>

Answer

<

Question 38

Which SQL function is used to count the number of rows in a table?

Accepted Answer

COUNT()

Answer

MIN()

Answer

SUM()

Answer

AVG()

Question 39

Which SQL statement is used to add a new row to the table 'Customers'?

Accepted Answer

INSERT INTO Customers (Name, Age) VALUES ('John Doe', 30)

Answer

ADD ROW TO Customers (Name = 'John Doe', Age = 30)

Answer

UPDATE Customers SET Name = 'John Doe' WHERE Age = 30

Question 40

Which SQL statement is used to modify the 'Name' field of a row in the 'Customers' table where the 'ID' is 1?

Accepted Answer

UPDATE Customers SET Name = 'New Name' WHERE ID = 1

Answer

MODIFY Customers SET Name = 'New Name' WHERE ID = 1

Answer

CHANGE Customers SET Name = 'New Name' WHERE ID = 1

Question 41

Which SQL statement is used to remove a row from the table 'Customers' where the 'ID' is 1?

Accepted Answer

DELETE FROM Customers WHERE ID = 1

Answer

REMOVE FROM Customers WHERE ID = 1

Answer

DELETE * FROM Customers WHERE ID = 1

Answer

DROP ROW FROM Customers WHERE ID = 1

Question 42

Which SQL keyword is used to create a foreign key constraint, referencing another table's primary key?

Accepted Answer

FOREIGN KEY

Answer

CONSTRAINT

Answer

PRIMARY KEY

Answer

REFERENCES