-- (Comment) (Transact-SQL)

text_of_comment

Is the character string that contains the text of the comment.

Use two hyphens (--) for single-line or nested comments. Comments inserted with -- are terminated by the newline character. There is no maximum length for comments. The following table lists the keyboard shortcuts that you can use to comment or uncomment text.

For more information about keyboard shortcuts, see SQL Server Management Studio Keyboard Shortcuts.

For multiline comments, see /*...*/ (Comment) (Transact-SQL).

The following example uses the -- commenting characters.

-- Choose the AdventureWorks2008R2 database.
USE AdventureWorks2008R2;
GO
-- Choose all columns and all rows from the Address table.
SELECT *
FROM Person.Address
ORDER BY PostalCode ASC; -- We do not have to specify ASC because 
-- that is the default.
GO

Tasks

Reference