SQL conventions¶

Sure, here’s a description of common SQL style conventions with examples using common MySQL commands:

Naming Conventions¶

Naming conventions refer to the rules and guidelines for naming database objects such as tables, columns, indexes, and stored procedures.

Use descriptive names: Choose names that clearly describe the purpose or content of the database object.

mysql> CREATE TABLE users (
mysql>     user_id INT AUTO_INCREMENT PRIMARY KEY,
mysql>     username VARCHAR(50),
mysql>     email VARCHAR(100)
mysql> );

Avoid abbreviations: Prefer full and meaningful words over abbreviations to enhance readability and understanding.

mysql> ALTER TABLE customers
mysql> ADD COLUMN date_of_birth DATE;

Indentation and Formatting¶

Indentation and formatting conventions improve the readability and maintainability of SQL code.

Indent SQL statements: Indent SQL statements consistently to show the logical structure of queries and commands.

mysql> SELECT
mysql>     user_id,
mysql>     username,
mysql>     email
mysql> FROM
mysql>     users
mysql> WHERE
mysql>     user_id = 1;

Use consistent casing: Use consistent casing for keywords, identifiers, and SQL functions to improve code consistency.

mysql> SELECT
mysql>     first_name,
mysql>     last_name,
mysql>     CONCAT_WS(' ', first_name, last_name) AS full_name
mysql> FROM
mysql>     customers;

Comments¶

Comments are annotations added to SQL code to explain its purpose, logic, or any other relevant information.

Document intent: Use comments to document the intent or purpose of SQL statements and code blocks.

mysql> -- Retrieve all active users
mysql> SELECT * FROM users WHERE status = 'active';

Avoid redundant comments: Avoid adding comments that merely repeat the code without adding meaningful information.

mysql> -- This query retrieves all users
mysql> SELECT * FROM users;

These SQL style conventions help maintain consistency, readability, and clarity in SQL code, making it easier to understand, debug, and maintain.

Advanced SQL features¶

Last update: 2024-05-03