MySQL · December 20, 2023

MySQL Command: INT

MySQL Command: INT

MySQL is a popular open-source relational database management system that is widely used for web applications and other data-driven projects. It offers a wide range of commands and functions to manipulate and query data efficiently. One such command is INT, which is used to define a column with an integer data type.

What is INT?

INT is short for "integer" and is a data type in MySQL that represents whole numbers. It can store both positive and negative values, ranging from -2147483648 to 2147483647. The INT data type is commonly used to store numeric data that does not require decimal places, such as IDs, counts, or quantities.

Creating an INT Column

To create an INT column in a MySQL table, you need to specify the column name and the INT data type. Here's an example:

CREATE TABLE users (
    id INT,
    name VARCHAR(50),
    age INT
);

In the above example, we create a table called "users" with three columns: "id" of type INT, "name" of type VARCHAR, and "age" of type INT.

INT Column Constraints

When creating an INT column, you can also specify additional constraints to enforce data integrity. Some commonly used constraints include:

  • NOT NULL: Ensures that the column cannot contain NULL values.
  • UNIQUE: Ensures that each value in the column is unique.
  • PRIMARY KEY: Combines the NOT NULL and UNIQUE constraints and designates the column as the primary key of the table.
  • AUTO_INCREMENT: Automatically generates a unique value for each new row inserted into the table.

Here's an example that demonstrates the usage of constraints:

CREATE TABLE products (
    id INT PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(50) NOT NULL,
    price DECIMAL(10, 2) NOT NULL,
    quantity INT DEFAULT 0
);

In the above example, the "id" column is defined as the primary key with the AUTO_INCREMENT constraint, ensuring that each new row inserted into the "products" table will have a unique ID. The "name" and "price" columns are defined as NOT NULL, meaning they must have a value. The "quantity" column has a DEFAULT constraint, which sets its value to 0 if no value is provided.

Querying INT Columns

Once you have created an INT column, you can perform various operations on it, such as inserting, updating, and querying data. Here are some examples:

INSERT INTO users (id, name, age) VALUES (1, 'John Doe', 25);

UPDATE users SET age = 26 WHERE id = 1;

SELECT * FROM users WHERE age > 30;

In the above examples, we insert a new row into the "users" table with an ID of 1, name of 'John Doe', and age of 25. We then update the age to 26 for the row with an ID of 1. Finally, we query the "users" table to retrieve all rows where the age is greater than 30.

Conclusion

The INT command in MySQL is a powerful tool for working with integer data. It allows you to define columns with whole numbers and perform various operations on them. By understanding how to create and manipulate INT columns, you can effectively manage and query your data in MySQL.

Summary:

In this article, we explored the MySQL command INT, which is used to define integer columns in a MySQL table. We learned that INT represents whole numbers and can store both positive and negative values. We also discussed how to create INT columns, apply constraints, and perform operations on them. If you are looking for reliable and high-performance VPS hosting solutions, consider Server.HK. With their top-notch VPS solutions, you can ensure the smooth operation of your MySQL databases.

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