Comments are text written by developers to leave an explanation in the code. Comments are ignored by the database. DB2 supports two types of comments:

/* */
--

Example

-- this is a comment
select * from employee; 
select * from employer; /* another comment */

Both SQL commands run with an error. Note that /* and */ have to end on the same line. They cannot span multiple lines. Noe that the following would produce an error message:

select * from employee; -- this is a comment

-- can only works if -- it the first non-space character.