/**
* @param QQClause[]|QQClause|null $objClauses QQClause object or array of QQClause objects
* @return QQSelect QQSelect clause containing all the nodes from all the QQSelect clauses from $objClauses,
* or null if $objClauses contains no QQSelect clauses
*/
public static function extractSelectClause($objClauses)
{
if ($objClauses instanceof QQSelect) {
return $objClauses;
}
if (is_array($objClauses)) {
$hasSelects = false;
$objSelect = QQuery::Select();
foreach ($objClauses as $objClause) {
if ($objClause instanceof QQSelect) {
$hasSelects = true;
$objSelect->Merge($objClause);
}
}
if (!$hasSelects) {
return null;
}
return $objSelect;
}
return null;
}
