/// <summary>
/// Reduces the node and then calls the visitor delegate on the reduced expression. The method throws an exception if the node is not reducible.
/// </summary>
/// <param name="visitor">An instance of <see cref="T:System.Func`2" />.</param>
/// <returns>
/// The expression being visited, or an expression which should replace it in the tree.
/// </returns>
protected override Expression VisitChildren(ExpressionVisitor visitor)
{
visitor.Visit(ColumnsExpression.Reduce());
visitor.Visit(TableExpression);
if (WhereExpression != null)
{
visitor.Visit(WhereExpression);
}
if (GroupByExpression != null)
{
visitor.Visit(GroupByExpression);
}
if (OrderByExpression != null)
{
visitor.Visit(OrderByExpression);
}
return(this);
}
/// <summary>
/// Sets the columns expression.
/// </summary>
/// <param name="columnExpression">The column expression.</param>
/// <exception cref="System.ArgumentException">'columnExpression' can be applied only once.;columnsExpression</exception>
public void SetColumnsExpression(ColumnsExpression columnExpression)
{
Check.NotNull(columnExpression, nameof(columnExpression));
_columnsExpression = columnExpression;
}