Question 1

What does SQL stand for?

Accepted Answer

SQL stands for Structured Query Language, which is the standard language for managing and querying relational databases.

Question 2

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

Accepted Answer

SELECT is the SQL command used to query and retrieve specific data from one or more database tables.

Question 3

What does a WHERE clause do in an SQL query?

Accepted Answer

The WHERE clause is used to filter records and retrieve only those rows that meet specified conditions in an SQL query.

Question 4

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

Accepted Answer

The UPDATE command is used to modify existing records or data in a database table.

Question 5

What is the primary key in a database table?

Accepted Answer

A primary key is a field or combination of fields that uniquely identifies each record in a table and cannot contain NULL or duplicate values.

Question 6

Which SQL keyword is used to add new records to a table?

Accepted Answer

The INSERT command is used to add new rows/records into an existing database table.

Question 7

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

Accepted Answer

SELECT is the SQL command used to fetch or retrieve data from one or more database tables.

Question 8

What does PRIMARY KEY constraint ensure in a database table?

Accepted Answer

PRIMARY KEY ensures that each record in a table is uniquely identified and does not contain NULL values.

Question 9

Which SQL clause is used to sort the result set in ascending or descending order?

Accepted Answer

ORDER BY clause is used to sort the result set in ascending (ASC) or descending (DESC) order based on specified columns.

Question 10

What does the SQL JOIN operation do?

Accepted Answer

JOIN combines rows from different tables based on a common column value to retrieve related data.

Question 11

Which SQL command is used to add new records into a table?

Accepted Answer

INSERT INTO command is used to insert new rows/records of data into a database table.

Question 12

What is the purpose of the FOREIGN KEY constraint in SQL?

Accepted Answer

FOREIGN KEY constraint creates a link between data in two tables and maintains referential integrity between them.

Question 13

Which SQL keyword is used to filter records based on specific conditions?

Accepted Answer

WHERE clause is used to filter records in SQL queries based on specified conditions.

Question 14

What is the primary purpose of using the WHERE clause in an SQL SELECT statement?

Accepted Answer

The WHERE clause filters and retrieves only those records from a table that meet the specified condition(s).

Question 15

Which SQL command is used to add a new record into an existing table in a database?

Accepted Answer

INSERT INTO is the correct SQL command to add new rows/records into an existing table with specified column values.

NDA Database Basics (SQL)

Database Basics (SQL) — Practice Questions