MySQL - Comments
The Comments are added in a MySQL statement with the purpose of making the statement easier to understand. It makes the MySQL statement more readable and hence easier to update it later. Comments are ignored when the statement is executed. In MySQL, 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
In MySQL, a single line comment can be done by two ways:
These single line comments will be ignored when the statement is executed.
In the example below, two line comments are used. Comments are ignored when the query is executed.
-- first line comment #second line comment SELECT Name, Salary FROM Employee; -- third 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 query is executed.
In the below MySQL statement, 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 MySQL statement will be: