SQL Server - Comments
The Comments are added in a SQL Server (Transact-SQL) statement with the purpose of making the statement easier to understand. It makes the statement more readable and hence easier to update it later. Comments are ignored when the statement is executed. In SQL Server (Transact-SQL), there are two ways of putting a comment.
- Single line comment
- Multi-line comment
Consider a database table called Employee with the following records:
Single line Comment
It starts with -- and ends with the end of that line. Anything after -- to the end of the line is a single line comment and will be ignored when the statement is executed.
In the example below, two line comments are used. Comments are ignored when query is executed.
-- first line comment SELECT Name, Salary FROM Employee; -- second line comment
This will produce the result as shown below:
It starts with /* and ends with */. Anything between /* and */ is a block comment and will be ignored when the query is executed.
In the below query, multi-line comments are used. When this query is executed these block of comments will be ignored.
/* comment line 1 comment line 2 */ SELECT EmpID, Name, City /* more comments */ FROM Employee;
This result of the above query will be: