SQL

Question 1

What does SQL stand for?

Answer 1

Structured Query Language

SQL is used specifically for relational databases.

Question 2

SQL is classified as a Domain-Specific Language (DSL). True or False?

Answer 2

TRUE

A DSL is used in specific circumstances, unlike general-purpose languages like JavaScript or Python.

Question 3

What is the purpose of the SELECT command in SQL?

Answer 3

To query data from a single table

Example: ‘SELECT x FROM y’ retrieves records from a specified table.

Question 4

Fill in the blank: The WHERE clause is used to _______.

Answer 4

narrow-down to a specific value or values

It allows for filtering results in SQL queries.

Question 5

Name the types of JOIN clauses in SQL.

Answer 5

• LEFT JOIN
• RIGHT JOIN
• FULL JOIN
• CROSS JOIN
• NATURAL JOIN
• INNER JOIN

JOIN clauses are used to query data from multiple tables.

Question 6

What are query aggregates used for in SQL?

Answer 6

• Total count
• Minimum and maximum values
• Sum
• Average

They allow for summarizing data returned from queries.

Question 7

What does CRUD stand for?

Answer 7

• Create
• Read
• Update
• Delete

CRUD represents the basic operations for managing data in a database.

Question 8

What is the C in CRUD?

Answer 8

Create

It refers to adding new data to the database.

Question 9

What is the R in CRUD?

Answer 9

Read

It refers to retrieving records from the database.

Question 10

What is the U in CRUD?

Answer 10

Update

It refers to editing existing records in the database.

Question 11

What is the D in CRUD?

Answer 11

Delete

It refers to removing records from the database.