protected override Expression VisitSelect(SelectExpression select)
{
select = (SelectExpression)base.VisitSelect(select);
if (select.Skip != null)
{
Expression expression3;
SelectExpression sel = select.SetSkip(null).SetTake(null);
if (select.IsDistinct || ((select.GroupBy != null) && (select.GroupBy.Count != 0)))
{
sel = sel.AddRedundantSelect(this.language, new TableAlias());
}
QueryType columnType = this.language.TypeSystem.GetColumnType(typeof(int));
sel = sel.AddColumn(new ColumnDeclaration("row__num", new RowNumberExpression(select.OrderBy), columnType)).AddRedundantSelect(this.language, new TableAlias());
sel = sel.RemoveColumn(sel.Columns.Single <ColumnDeclaration>(c => c.Name == "row__num"));
TableAlias alias = ((SelectExpression)sel.From).Alias;
ColumnExpression expression = new ColumnExpression(typeof(int), columnType, alias, "row__num");
if (select.Take != null)
{
expression3 = new BetweenExpression(expression, Expression.Add(select.Skip, Expression.Constant(1)), Expression.Add(select.Skip, select.Take));
}
else
{
expression3 = expression.GreaterThan(select.Skip);
}
if (sel.Where != null)
{
expression3 = sel.Where.And(expression3);
}
select = sel.SetWhere(expression3);
}
return(select);
}
protected override Expression VisitSelect(SelectExpression selectExpression)
{
selectExpression = (SelectExpression)base.VisitSelect(selectExpression);
if (((selectExpression.Skip != null) && (selectExpression.Take != null)) && (selectExpression.OrderBy.Count > 0))
{
Expression skip = selectExpression.Skip;
Expression take = selectExpression.Take;
Expression expression3 = PartialEvaluator.Eval(Expression.Add(skip, take));
selectExpression = selectExpression.SetTake(expression3).SetSkip(null);
selectExpression = selectExpression.AddRedundantSelect(this.language, new TableAlias());
selectExpression = selectExpression.SetTake(take);
selectExpression = (SelectExpression)OrderByRewriter.Rewrite(this.language, selectExpression);
IEnumerable <OrderExpression> orderBy = from ob in selectExpression.OrderBy select new OrderExpression((ob.OrderType == OrderType.Ascending) ? OrderType.Descending : OrderType.Ascending, ob.Expression);
selectExpression = selectExpression.SetOrderBy(orderBy);
selectExpression = selectExpression.AddRedundantSelect(this.language, new TableAlias());
selectExpression = selectExpression.SetTake(Expression.Constant(0));
selectExpression = (SelectExpression)OrderByRewriter.Rewrite(this.language, selectExpression);
IEnumerable <OrderExpression> enumerable2 = from ob in selectExpression.OrderBy select new OrderExpression((ob.OrderType == OrderType.Ascending) ? OrderType.Descending : OrderType.Ascending, ob.Expression);
selectExpression = selectExpression.SetOrderBy(enumerable2);
selectExpression = selectExpression.SetTake(null);
}
return(selectExpression);
}
