Returns a reference to the expressions array for this query.
Because this method returns by reference, alter hooks may edit the expressions array directly to make their changes. If just adding expressions, however, the use of addExpression() is preferred.
Note that this method must be called by reference as well:
$fields =& $query
->getExpressions();
A reference to the expression array structure.
Overrides SelectQueryInterface::getExpressions
public function &getExpressions() {
return $this->query
->getExpressions();
}