The new EJB QL (EnterpriseJavaBeans QueryLanguage) has a few restrictions (
see http://www.onjava.com/lpt/a/onjava/2001/09/19/ejbql.html).

One of them is that CommentsAreNotAllowed.

Q: Why would you comment queries?

''A: Optimizer hints are often done with comments.  Without support for comments, a common way of tuning SQL statements will be unavailable to you.''

However, EJB QL is not standard SQL and therefore optimizer hints have no place in EJB QL.  Furthermore, optimizer hints are very specific to database vendors.

That as may be, but they are still needed in the RealWorld.

Actually, optimiser hints are almost always a BadIdea. They have builtin assumptions about the state of your data which may not remain true over time, perhaps leading to your query being less efficient than it would otherwise.

''A2: Queries are code.  Code sometimes needs comments.'' (CommentsAreCode.)

----

Might I suggest that coded instructions to an optimizer are not comments?  They may use the comment syntax to separate them from normal code, but they are still code.

''Use of comment syntax for things that aren't comments to me sounds like an AntiPattern.''