<http://schema.org/articleBody>
" If GROUP BY or HAVING is used v Each column-name in the select list must identify a grouping expression, or be specified within an aggregate function, or be a correlated reference: - If the grouping expression is a column name, the select list may apply additional operators to the column name. For example, if the grouping expression is column C1, the select list may contain C1+1. - If the grouping expression is not a column name, the select list may not apply additional operators to the expression. For exa..."^^<http://www.w3.org/2001/XMLSchema#string>
<http://archive.midrange.com/midrange-l/201309/msg00857.html>