Exemplo n.º 1
0
        public static Statement CreateStatement(Select select, IEntityMapping mapping, IEnumerable <string> projectionOverride = null, bool noLock = false)
        {
            var sql        = new SqlWriter();
            var parameters = new Dictionary <string, object>();

            var projection    = projectionOverride ?? BuildProjection(select, mapping, parameters);
            var whereClause   = BuildWhereClause(select, mapping, parameters);
            var orderByClause = select.HasOrderBy ? BuildOrderBy(select.OrderBy, mapping, parameters) : null;

            Action <SqlWriter> writeProjection = x => x.Do(projection != null, y => y.FieldList(z => z.Comma.Flush(), projection), y => y.Wildcard.Flush());

            if (select.Any)
            {
                sql.Select.Cast().Trim().OpenBlock.Trim().Case.When.Exists.OpenBlock.Trim();
            }

            if (select.From.IsTable || select.HasConditions)
            {
                sql.Select.Flush();

                if (select.First || select.FirstOrDefault)
                {
                    sql.Top(1);
                }
                else if (select.Single)
                {
                    sql.Top(2);
                }
                else if (select.HasTop && !select.HasStart)
                {
                    sql.Do(select.TopType == Select.TopValueType.Count, x => x.Top(select.Top), x => x.TopPercent(select.Top));
                }

                if (select.Count)
                {
                    sql.CountWildcard.Flush();
                }
                else
                {
                    sql.Do(writeProjection);
                }

                sql.From.Flush();

                if (select.HasStart)
                {
                    sql.OpenBlock.Trim().Select.Do(writeProjection).Trim().Comma.
                    RowNumber().Over.OpenBlock.Trim().OrderBy.
                    Do(select.HasOrderBy, x => x.Write(orderByClause), x => x.Do(projection != null, writeProjection, y => y.QuotedName(mapping.Key.GetColumnName()))).Trim().
                    CloseBlock.As.RowNumberAlias.From.Flush();
                }

                if (select.HasDuplicates)
                {
                    var duplicateProjection = BuildProjection(select.Duplicates.Distinct, mapping, parameters);
                    sql.OpenBlock.Trim().Select.Do(writeProjection).Trim().Comma.
                    RowNumber().Over.OpenBlock.Trim().Partition.By.Write(duplicateProjection).OrderBy.Write(BuildOrderBy(select.Duplicates.OrderBy, mapping, parameters)).
                    Trim().CloseBlock.As.PartitionAlias.From.Flush();
                }
                else if (select.HasDistinct)
                {
                    var distinctProjection = BuildProjections(select.Distinct.Select(x => x.Projection), mapping, parameters);
                    sql.OpenBlock.Trim().Select.Do(writeProjection).Trim().Comma.
                    RowNumber().Over.OpenBlock.Trim().Partition.By.ExpressionList(z => z.Comma.Flush(), distinctProjection).OrderBy.
                    Write(BuildOrderBy(select.Distinct.Any(x => x.HasOrder) ? select.Distinct.Where(x => x.HasOrder).Select(x => x.Order) :
                                       select.Distinct.Select(x => new OrderBy {
                        Type       = OrderBy.SourceType.Projection,
                        Projection = x.Projection,
                        Order      = Order.Ascending
                    }), mapping, parameters)).Trim().
                    CloseBlock.As.PartitionAlias.From.Flush();
                }
            }

            switch (select.From.Type)
            {
            case Data.DataType.Table:
                sql.QuotedName(select.From.Table.Name).Write(select.From.Alias);
                if (noLock)
                {
                    sql.With(x => x.NoLock.Flush());
                }
                break;

            case Data.DataType.Query:
                var first = true;
                if (select.HasConditions)
                {
                    sql.OpenBlock.Trim().Flush();
                }
                foreach (var subQuery in select.From.Queries.Select(x => CreateStatement(x, mapping, projection, noLock)))
                {
                    sql.Do(!first, x => x.Union.Flush()).Write(subQuery.Text).Flush();
                    parameters.AddRange(subQuery.Parameters);
                    first = false;
                }
                if (select.HasConditions)
                {
                    sql.Trim().CloseBlock.As.Write(select.From.Alias).Flush();
                }
                break;
            }

            if (select.From.IsTable || select.HasConditions)
            {
                if (select.HasWhere || select.HasSetOperations)
                {
                    sql.Where.Write(whereClause).Flush();
                }

                if (select.Randomize)
                {
                    sql.OrderBy.NewId();
                }
                // The reason why we dont do an order by if there is a start is because the order by is
                // already specified in the row number definition. So we dont need to specify it again.
                else if (select.HasOrderBy && !select.HasStart && !select.HasDistinct)
                {
                    sql.OrderBy.Write(orderByClause);
                }

                if (select.HasDuplicates)
                {
                    sql.Trim().CloseBlock.As.Write(select.From.Alias).Where.PartitionAlias.GreaterThan.Value(1, SqlDbType.Int).Flush();
                }
                else if (select.HasDistinct)
                {
                    sql.Trim().CloseBlock.As.Write(select.From.Alias).Where.PartitionAlias.Equal.Value(1, SqlDbType.Int).Flush();
                }

                if (select.HasStart)
                {
                    sql.Trim().CloseBlock.As.Write(select.From.Alias).Where.RowNumberAlias.Flush();
                    if (select.HasTop && select.HasStart)
                    {
                        sql.Between(select.Start, select.Start + (select.Top - 1));
                    }
                    else
                    {
                        sql.GreaterThanOrEqual.Value(select.Start, SqlDbType.Int);
                    }
                }
            }

            if (select.Any)
            {
                sql.Trim().CloseBlock.Then.Value(1, SqlDbType.Bit).Else.Value(0, SqlDbType.Bit).End.As.Write(DataTypes.Bit.SqlName).Trim().CloseBlock.Flush();
            }

            return(new Statement(sql.ToString(), Statement.StatementType.Text, GetResultType(select), parameters));
        }