Exemple #1
0
        private static void LiftOrderBy(
            SelectExpression innerJoinSelectExpression,
            SelectExpression targetSelectExpression,
            TableExpressionBase innerJoinExpression)
        {
            var needOrderingChanges
                = innerJoinSelectExpression.OrderBy
                  .Any(x => x.Expression is SelectExpression ||
                       x.Expression.IsAliasWithColumnExpression() ||
                       x.Expression.IsAliasWithSelectExpression());

            var orderings = innerJoinSelectExpression.OrderBy.ToList();

            if (needOrderingChanges)
            {
                innerJoinSelectExpression.ClearOrderBy();
            }

            foreach (var ordering in orderings)
            {
                var orderingExpression = ordering.Expression;

                var aliasExpression = ordering.Expression as AliasExpression;

                if (aliasExpression?.Alias != null)
                {
                    var columnExpression = aliasExpression.TryGetColumnExpression();
                    if (columnExpression != null)
                    {
                        orderingExpression
                            = new ColumnExpression(
                                  aliasExpression.Alias,
                                  columnExpression.Property,
                                  columnExpression.Table);
                    }
                }

                var index = orderingExpression is SelectExpression
                    ? innerJoinSelectExpression.AddAliasToProjection(innerJoinSelectExpression.Alias + "_" + innerJoinSelectExpression.Projection.Count, orderingExpression)
                    : innerJoinSelectExpression.AddToProjection(orderingExpression);

                var expression = innerJoinSelectExpression.Projection[index];

                if (needOrderingChanges)
                {
                    innerJoinSelectExpression.AddToOrderBy(new Ordering(expression.TryGetColumnExpression() ?? expression, ordering.OrderingDirection));
                }

                var newExpression
                    = targetSelectExpression.UpdateColumnExpression(expression, innerJoinExpression);

                targetSelectExpression.AddToOrderBy(new Ordering(newExpression, ordering.OrderingDirection));
            }

            if ((innerJoinSelectExpression.Limit == null) &&
                (innerJoinSelectExpression.Offset == null))
            {
                innerJoinSelectExpression.ClearOrderBy();
            }
        }