Adding Comments to Queries
Comments can span multiple lines but cannot be nested inside one another. Comments are stored in the history database as part of the query.
To add comments to your queries
✔ For single-line comments, precede the comment with 2 dashes (--).
✔ For multiple-line comments, precede the comment with a forward slash and asterisk (/*), and follow the comment with an asterisk and forward slash (*/).
To temporarily comment out some of your SQL query
1 Highlight the code you want to comment out.
2 On the Query Window toolbar, click or press Ctrl+/ to comment out the highlighted text.
Note: If you select a comment, clicking on the 
icon removes the comment delimiter from around the selected comment, restoring the
contents as part of the query.