Basic MySQL Interview Questions

Here are some basic MySQL interview questions along with their answers:

1. What is MySQL?

• MySQL is an open-source relational database management system (RDBMS) that is widely used for storing and managing data.

1. What is a database in MySQL?

• In MySQL, a database is a collection of related data organized and structured for efficient storage, retrieval, and management.

1. What is a table in MySQL?

• In MySQL, a table is a structured collection of data stored in rows and columns. It represents a single entity or concept and consists of fields (columns) and records (rows).

1. How do you create a table in MySQL?

• To create a table in MySQL, you can use the CREATE TABLE statement. Here’s an example:
  CREATE TABLE employees ( id INT PRIMARY KEY, name VARCHAR(50), age INT, salary DECIMAL(10,2) );

1. How do you insert data into a table in MySQL?

• To insert data into a table in MySQL, you can use the INSERT INTO statement. Here’s an example:
  INSERT INTO employees (id, name, age, salary) VALUES (1, 'John Doe', 30, 50000);

1. How do you retrieve data from a table in MySQL?

• To retrieve data from a table in MySQL, you can use the SELECT statement. Here’s an example:
  SELECT * FROM employees;

1. What is the difference between DELETE and TRUNCATE statements in MySQL?

• The DELETE statement is used to remove specific rows from a table, based on a condition. It is slower and generates undo logs.
• The TRUNCATE statement is used to remove all rows from a table, effectively resetting the table to its initial state. It is faster and does not generate undo logs.

1. What is a primary key in MySQL?

• In MySQL, a primary key is a column (or a combination of columns) that uniquely identifies each record in a table. It ensures data integrity and allows for efficient data retrieval.

1. How do you establish a connection to a MySQL database using PHP?

• To establish a connection to a MySQL database using PHP, you can use the mysqli or PDO extension. Here’s an example using mysqli: $host = "localhost"; $username = "your_username"; $password = "your_password"; $database = "your_database"; $conn = mysqli_connect($host, $username, $password, $database); if (!$conn) { die("Connection failed: " . mysqli_connect_error()); }

1. What are some common data types used in MySQL?
   • Some common data types in MySQL include:
   • INT: for integer values
   • VARCHAR: for variable-length character strings
   • DECIMAL: for decimal numbers
   • DATE: for dates
   • TEXT: for large blocks of text

These are just a few basic MySQL interview questions to help you get started. It’s important to review and prepare for a wide range of topics to ensure you’re well-prepared for your interview.