How do I add the JIRA comments field in a custom query?

[Theme Grenz]

I am attempting to add the JIRA comment field to my custom query, though I do not see it as a default selection.  How do I do this in JIRA? 

Thank you!

[Nic Brough -Adaptavist-]

You can use comments in a query by saying "and comment ~ some-text"