Structured Query Language Quiz Class 12

Here’s a 15-question “Structured Query Language Quiz Class 12” based on the topics “Structured Query Language (SQL): Introduction, Data Definition Language (DDL), Data Manipulation Language (DML), Data Types (CHAR(n), VARCHAR(n), INT, FLOAT, DATE), Constraints (NOT NULL, UNIQUE, PRIMARY KEY), Create Database, Use Database, Show Databases, Drop Database, Show Tables, Create Table, Describe Table, Alter Table (Add and Remove an Attribute, Add and Remove Primary Key), Drop Table, Insert, Delete, Select, Operators (Mathematical, Relational, and Logical), Aliasing, Distinct Clause, Where Clause, In, Between, Order By, Meaning of Null, Is Null, Is Not Null, Like, Update Command, Delete Command, Aggregate Functions (MAX, MIN, AVG, SUM, COUNT), Group By, Having Clause, Joins (Cartesian Product on Two Tables, Equi-Join, and Natural Join)”

1. What does SQL stand for?

 Standard Query Language

 Simple Query Language

 Structured Query Language

 Structured Query Logic

2. What is the purpose of Data Definition Language (DDL) in SQL?

 To manipulate data

 To retrieve data from the database

 To define and manage the structure of a database

 To perform mathematical operations

3. Which data type is used for storing variable-length character strings in SQL?

 CHAR(n)

 INT

 VARCHAR(n)

 FLOAT

4. What does the NOT NULL constraint specify in SQL?

 Allows NULL values in the column

 Disallows NULL values in the column

 Enforces unique values in the column

 Creates a primary key

5. How can you create a new database in SQL?

 CREATE DATABASE database_name;

 USE DATABASE database_name;

 SHOW DATABASES;

 DROP DATABASE database_name;

6. What is the purpose of the SELECT statement in SQL?

 To insert data into a table

 To update data in a table

 To retrieve data from a table

 To delete data from a table

7. What is the meaning of the DISTINCT clause in SQL?

 Retrieves all records from a table

 Retrieves unique values from a specified column

 Deletes duplicate records from a table

 Updates existing records in a table

8. How can you filter data using the WHERE clause in SQL?

 SELECT DISTINCT column_name FROM table_name WHERE condition;

 SELECT * FROM table_name WHERE condition;

 DELETE FROM table_name WHERE condition;

 UPDATE table_name SET column_name = value WHERE condition;

9. What is the purpose of the GROUP BY clause in SQL?

 To sort data in ascending order

 To group rows that have the same values in specified columns

 To join two tables

 To add a new column to a table

10. How do you perform an equi-join in SQL?

 SELECT * FROM table1, table2 WHERE condition;

 SELECT * FROM table1 JOIN table2 ON condition;

 SELECT * FROM table1 INNER JOIN table2 ON condition;

 SELECT * FROM table1 LEFT JOIN table2 ON condition;

11. What does the UPDATE command in SQL do?

 Deletes records from a table

 Modifies existing records in a table

 Adds a new table to the database

 Retrieves data from a table

12. Which keyword is used for removing records from a table in SQL?

 DELETE

 REMOVE

 DROP

 ERASE

13. What is the purpose of the HAVING clause in SQL?

 To filter rows based on a condition

 To filter aggregate functions’ results

 To create an alias for a column

 To group rows based on a condition

14. What does the MAX() function do in SQL?

 Calculates the average value

 Retrieves the maximum value in a column

 Counts the number of rows

 Retrieves the minimum value in a column

15. What is a Cartesian product in SQL?

 The result of multiplying the number of rows in two tables

 A type of join that combines rows based on common values

 The process of creating a new table

 A function to calculate the average

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