TN 12th Computer Science Unit 4 - Structured Query Language (SQL) - New Sample Question Papers Study Material - QB365 Set A | QB365

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TN 12th Computer Science Unit 4 - Structured Query Language (SQL) - New Sample Question Papers Study Material - QB365 Set A

Published on: 22/08/2026

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Std: 12th Standard - Computer Science

chapter: Unit 4 - Structured Query Language (SQL) - New - Sample Question Papers

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Questions:

Choose the correct answer

10 x 1 = 10

Which of the following SQL DDL command used to create a table?

(a)

CREATE

(b)

CREATE TABLE

(c)

NEW TABLE

(d)

DDL TABLE

Double data type precision may exceed

(a)

(b)

(c)

(d)

SQL stands for

(a)

Standard Query Language

(b)

Secondary Query Language

(c)

Structured Query Language

(d)

Standard Question Language

_______________ command is used to remove a table form the database.

(a)

DELETE ALL

(b)

DROP TABLE

(c)

ALTER TABLE

(d)

DELETE

The statement in SQL is used to retrieve data from a table in a database:

(a)

SELECT

(b)

CREATE

(c)

DISTINCT

(d)

ORDER BY

The clause used to sort data in a database

(a)

SORT BY

(b)

ORDER BY

(c)

GROUP BY

(d)

SELECT

Queries can be generated using

(a)

SELECT

(b)

ORDER BY

(c)

MODIFY

(d)

ALTER

The command to delete a table including the structure is

(a)

DROP

(b)

DELETE

(c)

DELETE ALL

(d)

ALTER TABLE

Which command lets to change the structure of the table?

(a)

SELECT

(b)

ORDER BY

(c)

MODIFY

(d)

ALTER

10.

Which commands provide definitions for creating table structure, deleting relations, and modifying relation schemas.

(a)

DDL

(b)

DML

(c)

DCL

(d)

DQL

Very Short Answer

8 x 2 = 16

11.

Differentiate BETWEEN AND NOT BETWEEN keywords.

12.

What are two basic types of DML.

13.

Expand

(i) SQL

(ii) DBMS

(iii) RDBMS

14.

What is the difference between SOL and MySQL?

15.

Which component of SQL lets insert values in tables and which lets to create a table?

16.

Write the difference between table constraint and column constraint.

17.

Differentiate Unique and Primary Key constraint

18.

Write a query that selects all students whose age is less than 18 in order wise.

Short Answer

8 x 3 = 24

19.

List the data types used in SQL.

20.

Write the syntax for the following commands.

(i) INSERT

(ii) DELETE

(iii) UPDATE

21.

Compare Delete, Truncate and Drop in SQL.

(or)

What is the use of DELETE, TRUNCATE and DROP commands in SQL?

22.

Write a SQL statement using DISTINCT keyword.

23.

Write the use of Savepoint command with an example.

24.

Write any three DDL commands.

25.

Write a SQL statement to modify the student table structure by adding a new field.

26.

What is a constraint? Write short note on Primary key constraint.

Long Answers

5 x 5 = 25

27.

Explain ALTER command in detail.

28.

Write the processing skills of SQL.

29.

Write a SQL statement to create a table for employee having any five fields and create a table constraint for the employee table

30.

Construct the following SQL statements in the student table.

(i) SELECT statement using GROUP BY clause.

(ii) SELECT statement using ORDER BY clause.

31.

What are the components of SQL? Write the commands in each.

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Answers Key:

Choose the correct answer

10 x 1 = 10

(b)
CREATE TABLE

(a)
64

(b)
DROP TABLE

(a)
SELECT

(b)
ORDER BY

(a)
SELECT

(a)
DROP

(d)
ALTER

10.

(a)
DDL

Very Short Answer

8 x 2 = 16

11.

BETWEEN	NOT BETWEEN
The BETWEEN keyword defines a range of values the record must fall into to make the condition true.	The NOT BETWEEN is reverse of the BETWEEN operator where the records not satisfying the condition are displayed.

12.

The DML is basically of two types :

(i) Procedural DML Requires a user to specify what data is needed and how to get it.

(ii) Non-Procedural DML - Requires a user to specify what data is needed without specifying how to get it.

13.

(i) SQL -Structured Query Language

(ii) DBMS-Database Management System
(iii) RDBMS- Relational Database Management System.

14.

SQL	MySQL
Structured Query Language is a language used for accessing databases.	MySQL is a database management system, like SQL Server, Oracle, Informix, Postgres, etc.
SQL is a DBMS	MySQL is a RDBMS

15.

Command	Description	Component
Insert	Inserts data into a table	DML
Create	To create tables in the database	DDL

16.

Table constraint	Column constraint
Table constraint is apply to a group of one or more columns.	Column constraint apply only to individual column

17.

	Unique Key Constraint	Primary Key Constraint
(i)	This constraint ensures that no two rows have the same value in the specified columns.	This constraint declares a field as a Primary Key which helps to uniquely identify a record.
(ii)	The UNIQUE constraint can be applied only to fields that have also been declared as NOT NULL.	The Primary Key does not allow NULL values.

18.

Query : SELECT * FROM student WHERE Age < 18 ORDERBY Name;

Short Answer

8 x 3 = 24

19.

(i) char (Character)

(ii) varchar

(iii) dec (Decimal)

(iv) numeric

(v) int (Integer)

(vi) smallint

(vii) float

(viii) real

(ix) double

20.

(i) INSERT:

INSERT INTO <table-name> [column-list] VALUES (values);

(ii) DELETE :

DELETE FROM table-name WHERE condition;

(iii) UPDATE :

UPDATE SET column-name = value, column-name = value,.. WHERE condition;

21.

Delete

Truncate

Drop

The DELETE command

permanently removes one or more records from the table. It removes the

entire row, not individual fields of the row. so no

field arguments is needed.

Syntax :

DELETE FROM table

name WHERE condition;

The TRUNCATE

command is used to delete all the rows from the table,

the structure remains and the space is freed from the table.

Syntax:

TRUNCATE

TABLE table-name;

The DROP TABLE command is used to remove a table from

the database. once a table

is dropped we cannot

get it back. so be careful

while using DROP TABLE

command.

Syntax :

DROP TABLE table-name;

22.

(i) The DISTINCT keyword is used along with the SELECT command to eliminate duplicate rows in the table. This helps to eliminate redundant data.

Admno	Name	Gender	Place
100	Ashish	M	Chennai
101	Adarsh	M	Delhi
102	Akshith	M	Bangalore
103	Ayush	M	Delhi

(ii) For Example: SELECT DISTINCT PIace FROM Student;

Will display the following data as follows:

Place

Chennai

Bangalore

Delhi

23.

The SAVEPOINT Command is used to temporarily save a transaction so that you can rollback to the point whenever required.
Example: SAVEPOINT savepoint_name;

UPDATE Student SET Name = Mini WHERE Admno=105;

SAVEPOINT A;

24.

Data Definition Language :

(i) Create Command : To create tables in the database.

(ii) Alter Command : The ALTER command is used to alter the table.

(iii) Drop Command : The DROP TABLE command is used to remove a table from the database.

25.

ALTER TABLE <table-name> ADD <column-name><data type><size>;

Example :ALTER TABLE Student ADD Address
CHAR (25)

26.

(i) Constraint is a condition applicable on a field or set of fields.

Primary Key Constraint :

(i) This constraint declares a field as a Primary key which helps to uniquely identify a record.

(ii) It is similar to unique constraint except that only one field of a table can be set as primary key.

(iii) The primary key does not allow NULL value.

Long Answers

5 x 5 = 25

27.

ALTER Command:

(i) The ALTER Command is used to alter the table structure like adding a column, renaming the existing column, change the data type of
any column or size of the column or delete the column from the table. It is used in the following way :

ALTER TABLE <Table-name> ADD

<column-name><data type><size>;

(ii) To add a new column "Address" of type char to the Student table, the command is used as

ALTER TABLE Student ADD Address char;

(ii) To modify existing column of table, the ALTER TABLE command can be used with MODIFY clause like wise:

ALTER <table-name> MODIFY

<column-name><data type><size>;

ALTER TABLE Student MODIFY Address char (25);

(iv) The ALTER command can be used to rename an existing column in the following way:

ALTER TABLE <table-name> CHANGE old column-name new-column name new column definition;

(v) The ALTER command can also be used to remove a column or all columns,
ALTER TABLE DROP COLUMN <column-names>;

28.

The various processing skills of SQL are :

(i) Data Definition Language (DDL) : The SQL DDL provides commands for defining relation schemas (structure), deleting relations, creating indexes and modifying relation schemas.

(ii) Data Manipulation Language (DML): The SQL DML includes commands to
insert, delete, and modify tuples in the database.

(iii) Embedded Data Manipulation Language : The embedded form of SQL is used in high level programming languages.

(iv) View Definition : The SQL also includes commands for defining views of tables.

(v) Authorization : The SQL includes commands for access rights to relations and views of tables.

(vi) Integrity : The SQL provides forms for integrity checking using condition.

(vii) Transaction control: The SQL includes commands for file transactions and control over transaction processing.

29.

CREATE TABLE employee

(

eempcode INTEGER NOT NULL,

name CHAR(20),

desig CHAR(20),

pay INTEGER,

allowance INTEGER,

PRIMARY KEY (empcode)

);

30.

(i) GROUP BY clause :

• The GROUP BY clause is used with the SELECT statement to group the students on rows or columns having identical values or divide the table in to groups.

• For example to know the number of male students or female students of a class, the GROUP BY clause may be used.

• The syntax for the GROUP BY clause is

• SELECT <column-names> FROM <table-name> GROUP BY <column-name>

HAVING condition];

• To apply the above command on the student table:

• SELECT Gender FROM Student GROUP BY Gender;

• The following command will give the below given result:

Gender
M
F

• SELECT Gender, count(*) FROM Student GROUP BY Gender;

Gender	count(*)
M	5
F	3

(ii) ORDER BY clause :

• The ORDER BY clause in SQL is used to sort the data in either ascending
or descending based on one or more columns.

(a) By default ORDER BY sorts the data in ascending order.

(b) We can use the keyword DESC to sort the data in descending order and the keyword ASC to sort in ascending order.

• The ORDER BY clause is used as :

• SELECT <column-name> [,<column-name>....] FROM <table-name>ORDER BY<column1>,<column2>,....ASC| DESC;

• Example:

To display the students in alphabetical order of their names, the command is used as

• SELECT * FROM Student ORDER BY Name;

The above student table is arranged as follows :

Admno	Name	Gender	Age	Place
104	Abinandh	M	18	Chennai
101	Adarsh	M	18	Delhi
102	Akshith	M	17	Bangalore
100	Ashish	M	17	Chennai
103	Ayush	M	18	Delhi
106	Devika	F	19	Bangalore
107	Hema	F	17	Chennai
105	Revathi	F	19	Chennai

31.

Components of SQL: SQL commands are divided into five categories:

Data Definition Language :

(i) The Data Definition Language (DDL) consist of SQL statements used to define the database structure or schema.

(ii) It simply deals with descriptions of the database schema and is used to create and modify the structure of database objects in databases.

(iii) SQL commands which comes under Data Definition Language are :

Create	To create tables in the database.
Alter	Alters the structure of the database.
Drop	Delete tables from database.
Truncate	Remove all records from a table, also release the space occupied by those records.

Data Manipulation Language :

(i) A Data Manipulation Language (DML) is a query language used for adding (inserting), removing (deleting). and modifying (updating) data in a database.

(ii) SQL commands which comes under Data Manipulation Language are :

Insert	Inserts data into a table
Update	Updates the existing data within a table.
Delete	Deletes all records from a table, but not the space occupied by them.

Data Control Language :

(i) A Data Control Language (DCL) is a programming language used to control the access of data stored in a database. It is used for controlling privileges in the database (Authorization).

(ii) SQL commands which come under Data Control Language are :

Grant	Grants permission to one or more users to perform specific tasks.
Revoke	Withdraws the access permission given by the GRANT statement.

Transactional Control Language :

(i) Transactional control language (TCL) commands are used to manage transactions in the database. These are used to manage the changes made to the data in a table by DML statements.

(ii) SQL command which come under Transfer Control Language are :