SQL Comment

Galaxy Glossary

How do you add comments in SQL?

SQL comments are used to explain SQL code. They are ignored by the database system and are helpful for documentation. Comments improve readability and maintainability of queries.

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Description

Comments in SQL are annotations within your code that are ignored by the database system when executing queries. They serve as valuable documentation, making your code easier to understand and maintain, especially in larger projects. They are crucial for explaining complex logic, clarifying the purpose of different sections, and helping other developers (or your future self) comprehend the code's functionality. Comments are particularly helpful when working with intricate queries or procedures. They allow you to add explanatory notes directly into the code, enhancing its readability and maintainability. This is a fundamental aspect of writing clean and understandable SQL code.

Why SQL Comment is important

Comments are essential for maintaining and understanding SQL codebases. They improve collaboration among developers and make it easier to modify or debug queries in the future. Clear comments reduce the time spent deciphering complex logic.

Example Usage


-- Sample table: Orders
CREATE TABLE Orders (
    OrderID INT PRIMARY KEY,
    OrderDate DATE,
    CustomerName VARCHAR(50)
);

INSERT INTO Orders (OrderID, OrderDate, CustomerName)
VALUES
(1, '2023-01-15', 'Alice'),
(2, '2023-02-20', 'Bob'),
(3, '2023-01-10', 'Charlie'),
(4, '2023-03-05', 'David'),
(5, '2023-01-25', 'Eve');

-- Query to find orders placed between January 10, 2023, and January 25, 2023 (inclusive)
SELECT OrderID, OrderDate, CustomerName
FROM Orders
WHERE OrderDate BETWEEN '2023-01-10' AND '2023-01-25';

Common Mistakes

Forgetting to use comments to explain complex queries.
Using comments that are too brief or vague, failing to provide sufficient context.
Not using consistent commenting styles across the codebase.

SQL Comment

How do you add comments in SQL?

Description

Why SQL Comment is important

Example Usage

Common Mistakes

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