public virtual Expression VisitSqlGroupingSelectExpression (SqlGroupingSelectExpression expression)
{
ArgumentUtility.CheckNotNull ("expression", expression);
var groupExpressions = new[] { expression.KeyExpression }.Concat (expression.AggregationExpressions);
CommandBuilder.AppendSeparated (", ", groupExpressions, (cb, exp) => VisitExpression (exp));
return expression;
}