looking at documentation again. one very minor question (issue) + <para> + The <literal>ON EMPTY</literal> clause specifies the behavior if the + <replaceable>path_expression</replaceable> yields no value at all; the + default when <literal>ON EMPTY</literal> is not specified is to return + a null value. + </para>
I think it should be: applying <replaceable>path_expression</replaceable> or evaluating <replaceable>path_expression</replaceable> not "the <replaceable>path_expression</replaceable>" ?
