In PostgreSQL, you can add comments to your SQL code to make it more understandable and maintainable. There are two types of comments you can use: single-line comments and multi-line comments. As the name suggests multi-line comments will span across multiple lines. Let see how to insert a single line and multi line comment in PostgreSQL with example for each.
Single line and Multi line comment in PostgreSQL:
Single Line comment in PostgreSQL:
The syntax for creating a single line comment in PostgreSQL is — symbol. Single-line comments start with — and continue to the end of the line. Everything after — on that line is considered a comment and is ignored by the SQL parser.
-- comment goes here
Example – Single line comment in PostgreSQL
Example 1:
You can create a SQL comment on a single line in PostgreSQL as shown below
-- selecting everything from Table1 <em>Select * from Table1;</em>
Example 2:
-- This is a single-line comment SELECT * FROM employees; -- This comment is also single-line
Multiline comment in PostgreSQL:
The syntax for creating a multi line comment in PostgreSQL starts with /* and ends with */ symbol. They can span multiple lines.
/* comment goes here */
Example – Multi line comment in PostgreSQL:
You can create a SQL comment on multiple lines in PostgreSQL as shown below
/* selecting everything from Table1 Author: postgresqldatascience.com */ Select * from Table1;
Summary:
Here is a practical example combining both single-line and multi-line comments in PostgreSQL
-- Retrieve all records from the employees table SELECT * FROM employees; -- This selects all columns and rows /* The following query retrieves all records from the departments table. We use this to get a list of all departments in the company. */ SELECT * FROM departments; /* Example ends */
Using comments effectively can help make your SQL scripts easier to read and understand, especially for others who may work with your code in the future.
