Mastering SQL Commands and Functions

What does SQL stand for?

• Standard Query Language

• Structured Query Language

• Structured Query List

• Simple Query Language

Which command is used to retrieve data from a database?

• INSERT

• UPDATE

• SELECT

• DELETE

What is the purpose of the INSERT command in SQL?

• To add new records to a database table.

• To delete existing records from a database table.

• To retrieve data from a database table.

• To update existing records in a database table.

Which SQL command is used to modify existing records?

• SELECT

• INSERT

• UPDATE

• DELETE

What does the DELETE command do in SQL?

• The DELETE command retrieves data from a table.

• The DELETE command updates existing rows in a table.

• The DELETE command adds rows to a table.

• The DELETE command removes rows from a table.

What is a primary key in a database?

• A primary key is a unique identifier for a record in a database.

• A primary key is an optional field in a database.

• A primary key can be duplicated across records.

• A primary key is a type of foreign key.

Name one aggregate function in SQL.

• AVG

• SUM

• MAX

• COUNT

What does the COUNT() function do?

• Counts the number of rows in a dataset.

• Retrieves unique values from a dataset.

• Finds the maximum value in a dataset.

• Calculates the average of a dataset.

How do you calculate the average of a column in SQL?

• SELECT MAX(column_name) FROM table_name;

• SELECT SUM(column_name) FROM table_name;

• SELECT COUNT(column_name) FROM table_name;

• SELECT AVG(column_name) FROM table_name;

What is the purpose of the GROUP BY clause?

• To join multiple tables together.

• To sort rows in ascending order.

• To filter rows based on a condition.

• To group rows that have the same values in specified columns.