SQL Comments

This example has a comment describing the SQL.

/* 
 * List all customers from Sweden 
 */
SELECT FirstName, LastName, City, Country 
  FROM Customer
 WHERE Country = 'Sweden'

The comments are ignored and the SQL executes as usual.

Single-line syntax.

-- SQL description

Multi-line syntax.

/* SQL description
   SQL description
   SQL description
   SQL description */

-- List all suppliers in Brazil

SELECT CompanyName, ContactName, City, Country, Phone
  FROM Supplier
 WHERE Country = 'Brazil'

Again, the comment is ignored and the SQL executes as usual.

/************************************************
 * List the monthly orders for American customers 
 * for the year 2013. Order the list by month.
 ************************************************/

SELECT MONTH(OrderDate) AS Month,
       FirstName, LastName,
       SUM(TotalAmount) AS 'Monthly Sales'
  FROM [Order] O 
  JOIN Customer C ON C.Id = O.CustomerId
 WHERE Country = 'USA' AND YEAR(OrderDate) = 2013
 GROUP BY FirstName, LastName, MONTH(OrderDate)
 ORDER BY MONTH(OrderDate)

This commenting style is referred to as a flower-box.

Month	FirstName	LastName	Monthly Total
1	Art	Braunschweiger	485.00
1	Paula	Wilson	3868.60
1	Yoshi	Latimer	102.40
2	Jose	Pavarotti	7889.10
2	Rene	Phillips	1755.00

SELECT FirstName /*, LastName */ 
  FROM Customer
 WHERE Country = 'Sweden'

This hiding technique is referred to as commenting out the code.

• Our Sql Constraints Reference
• Our HTML Comment Reference
• Our CSS Comments Tutorial