/*...*/ (Comment) (Transact-SQL)
Indicates user-provided text. The text between the /* and */ is not evaluated by the server.
Transact-SQL Syntax Conventions
Comments can be inserted on a separate line or within a Transact-SQL statement. Multiple-line comments must be indicated by /* and */. A stylistic convention often used for multiple-line comments is to begin the first line with /*, subsequent lines with **, and end with */.
There is no maximum length for comments.
Nested comments are supported. If the /* character pattern occurs anywhere within an existing comment, it is treated as the start of a nested comment and, therefore, requires a closing */ comment mark. If the closing comment mark does not exist, an error is generated.
For example, the following code generates an error.
DECLARE @comment AS varchar(20); GO /* SELECT @comment = '/*'; */ SELECT @@VERSION; GO
To work around this error, make the following change.
DECLARE @comment AS varchar(20); GO /* SELECT @comment = '/*'; */ */ SELECT @@VERSION; GO
The following example uses comments to explain what the section of the code is supposed to do.
USE AdventureWorks; GO /* This section of the code joins the Contact table with the Address table, by using the Employee table in the middle to get a list of all the employees in the AdventureWorks database and their contact information. */ SELECT c.FirstName, c.LastName, a.AddressLine1, a.AddressLine2, a.City FROM Person.Contact c JOIN HumanResources.Employee e ON c.ContactID = e.ContactID JOIN HumanResources.EmployeeAddress ea ON e.EmployeeID = ea.EmployeeID JOIN Person.Address a ON ea.AddressID = a.AddressID; GO
Reference
-- (Comment) (Transact-SQL)Control-of-Flow Language (Transact-SQL)
