MySQL

What are the different data types available in SQL?

• integer, float, char, varchar, date, time, timestamp, boolean

• text

• string

• double

Explain the concept of SQL Joins with an example.

• An example of SQL Join would be: SELECT Orders.OrderID, Customers.CustomerName FROM Orders RIGHT JOIN Customers ON Orders.CustomerID = Customers.CustomerID;

• SELECT Orders.OrderID, Customers.CustomerName FROM Orders LEFT JOIN Customers ON Orders.CustomerID = Customers.CustomerID;

• An example of SQL Join would be: SELECT Orders.OrderID, Customers.CustomerName FROM Orders INNER JOIN Customers ON Orders.CustomerID = Customers.CustomerID;

• An example of SQL Join would be: SELECT Orders.OrderID, Customers.CustomerName FROM Orders CROSS JOIN Customers ON Orders.CustomerID = Customers.CustomerID;

What are Aggregate Functions in SQL? Provide examples.

• Aggregate functions in SQL are functions that operate on a set of values to return a single value. Examples include COUNT(), SUM(), AVG(), MIN(), and MAX().

• Aggregate functions in SQL return multiple values instead of a single value

• Examples of Aggregate Functions in SQL include DELETE() and UPDATE()

• Aggregate functions in SQL are functions that operate on a single value

Discuss the importance of SQL Constraints in database management.

• SQL Constraints play a crucial role in maintaining data integrity and consistency in a database by enforcing rules on the data stored in tables.

• SQL Constraints are primarily used for data encryption in databases.

• SQL Constraints are unnecessary and slow down database operations.

• SQL Constraints are only used for aesthetic purposes in database design.

How are Subqueries used in SQL? Provide a scenario.

• Subqueries are used in SQL to combine multiple tables into one result set.

• Subqueries are used in SQL to sort data in descending order.

• Subqueries are used in SQL to update multiple records in a single query.

• Subqueries are used in SQL to nest one query within another query, allowing for more complex and specific data retrieval.

Explain the concept of Normalization in SQL databases.

• Normalization involves combining large tables into a single table

• Normalization does not involve defining relationships between tables

• Normalization in SQL databases is the process of organizing data in a database efficiently. It involves reducing data redundancy and dependency by dividing large tables into smaller ones and defining relationships between them using foreign keys.

• Normalization is the process of adding redundancy to data in a database

Write a sample INSERT query in SQL.

• INSERT INTO table_name (column1, column2, column3) VALUE (value1, value2, value3);

• INSERT INTO table_name VALUES (value1, value2, value3);

• INSERT INTO table_name (column1, column2, column3) VALUES (value1, value2, value3);

• INSERT INTO table_name (column1, column2) VALUES (value1, value2);

How does a SELECT query work in SQL? Provide an example.

• SELECT column1, column2 FROM table_name WHERE condition

• SELECT * FROM table_name

• SELECT column1, column2 WHERE condition

• SELECT column1, column2 FROM table_name ORDER BY column1

What is the purpose of a DELETE query in SQL? Give an example.

• DELETE * table_name WHERE condition;

• DELETE FROM table_name WHERE condition;

• REMOVE FROM table_name WHERE condition;

• DROP FROM table_name WHERE condition;

Which data type would you use for storing a date in SQL?

• DATE

• DATETIME

• TIME

• STRING