Fundamentals of SQL

What is the purpose of SQL data types?

• The purpose of SQL data types is to specify the type of data that can be stored in a column, ensuring data integrity and optimizing storage.

• To manage database permissions

• To define the structure of SQL queries

• To create user accounts in a database

Which SQL data type is used to store text?

• DATE

• INT

• VARCHAR or TEXT

• FLOAT

Write a basic SQL query to select all columns from a table named 'employees'.

• SELECT employees.*;

• SELECT * FROM employees;

• GET * FROM employees;

• SELECT ALL FROM employees;

What is the result of the following SQL query: SELECT COUNT(*) FROM orders?

• A boolean indicating if the orders table is empty.

• A list of all unique values in the orders table.

• An integer representing the total number of rows in the orders table.

• A string representing the first row in the orders table.

Explain the difference between INNER JOIN and LEFT JOIN.

• INNER JOIN returns matching rows from both tables; LEFT JOIN returns all rows from the left table and matched rows from the right table.

• INNER JOIN returns only unmatched rows from both tables; LEFT JOIN returns all rows from the right table.

• INNER JOIN returns all rows from both tables; LEFT JOIN returns matching rows from the right table.

• INNER JOIN returns all rows from the right table; LEFT JOIN returns only matching rows from both tables.

What SQL function would you use to find the maximum value in a column?

• SUM()

• COUNT()

• MAX()

• AVG()

Which operator is used to filter records in a SQL query?

• SELECT

• FILTER

• ORDER BY

• WHERE

What command is used to insert new records into a table?

• ADD RECORDS TO

• UPDATE TABLE WITH

• INSERT INTO

• CREATE NEW ENTRY

How do you update an existing record in a SQL table?

• UPDATE table_name SET column1 = value1, column2 = value2 WHERE condition;

• DELETE FROM table_name WHERE condition;

• SELECT * FROM table_name WHERE condition;

• INSERT INTO table_name VALUES (value1, value2);

What is the purpose of the DELETE statement in SQL?

• To update existing rows in a table.

• To retrieve data from a table.

• To remove rows from a table in a database.

• To create a new table in the database.