public partial class PartLinkQueryProvider : IQueryProvider<PartLinkInfo>
    {
        public readonly IParamManager<PartLinkParams> PartLinkParams;
        private readonly IInnerPartLinkSwitcher innerPartLinkSwitcher;

        public PartLinkQueryProvider(
            IParamManager<PartLinkParams> partLinkParams, IInnerPartLinkSwitcher innerPartLinkSwitcher)
        {
            PartLinkParams = partLinkParams;
            this.innerPartLinkSwitcher = innerPartLinkSwitcher;
        }
    }

    public partial class PartLinkInfo
    {
    }

    public partial class PartLinkParams
    {
    }

    public interface IInnerPartLinkSwitcher
    {
        void AddSubQuery(Action<bool> action);
    }

    public class WithoutInnerPartLinkSwitcher : IInnerPartLinkSwitcher
    {
        public void AddSubQuery(Action<bool> action)
        {
            //no-op
        }
    }

    public class WithInnerPartLinkSwitcher : IInnerPartLinkSwitcher
    {
        public readonly IParamManager<InnerPartLinkParams> InnerPartLinkParams;
        private readonly bool latestPublicationOnly;

        public WithInnerPartLinkSwitcher(
            IParamManager<InnerPartLinkParams> innerPartLinkParams, bool latestPublicationOnly)
        {
            InnerPartLinkParams = innerPartLinkParams;
            this.latestPublicationOnly = latestPublicationOnly;
        }

        public void AddSubQuery(Action<bool> action)
        {
            action(latestPublicationOnly);
        }
    }

    public partial class InnerPartLinkParams
    {
    }

    public partial class PartLinkParams
    {
        public readonly Guid GenericServicePartsPageID;
        public readonly Guid ModelPublicationID;
        public readonly Guid ServicePartsPageID;

        public PartLinkParams(Guid genericServicePartsPageID, Guid modelPublicationID, Guid servicePartsPageID)
        {
            GenericServicePartsPageID = genericServicePartsPageID;
            ModelPublicationID = modelPublicationID;
            ServicePartsPageID = servicePartsPageID;
        }
    }

    public partial class InnerPartLinkParams
    {
        public readonly Guid ModelID;
        public readonly string LanguageCode;

        public InnerPartLinkParams(Guid modelID, string languageCode)
        {
            ModelID = modelID;
            LanguageCode = languageCode;
        }
    }

    public partial class PartLinkInfo
    {
        public string PartNumber { get; set; }
    }

        public static void Main()
        {
            ExecutePartLinkQuery(
                dbCommand =>
                new PartLinkQueryProvider(
                    new PartLinkParams(
                        new Guid("..."),
                        new Guid("..."),
                        new Guid("...")
                        ).AsQueryParams(dbCommand),
                    new WithoutInnerPartLinkSwitcher()
                    )
                );

            ExecutePartLinkQuery(
                dbCommand =>
                new PartLinkQueryProvider(
                    new PartLinkParams(
                        new Guid("..."),
                        new Guid("..."),
                        new Guid("...")
                        ).AsQueryParams(dbCommand),
                    new WithInnerPartLinkSwitcher(
                        new InnerPartLinkParams(
                            new Guid("..."),
                            "en"
                            ).AsQueryParams(dbCommand),
                        false
                        )
                    )
                );

            ExecutePartLinkQuery(
                dbCommand =>
                new PartLinkQueryProvider(
                    new PartLinkParams(
                        new Guid("..."),
                        new Guid("..."),
                        new Guid("...")
                        ).AsQueryParams(dbCommand),
                    new WithInnerPartLinkSwitcher(
                        new InnerPartLinkParams(
                            new Guid("..."),
                            "en"
                            ).AsQueryParams(dbCommand),
                        true
                        )
                    )
                );
        }

        private static void ExecutePartLinkQuery(
            Func<DbCommand, IQueryProvider<PartLinkInfo>> queryProviderFunc)
        {
            var dbCommand = ...
            var queryProvider = queryProviderFunc(dbCommand);

            queryProvider.FillDbCommand(dbCommand);

            using (var reader = dbCommand.ExecuteReader())
            {
                while (reader.Read())
                {
                    PartLinkInfo partLinkInfo = queryProvider.Materialize(reader);
                    Console.WriteLine(partLinkInfo.PartNumber);
                }
            }
        }

G> "Декомпозиция строк" надо записать.

SELECT
    A
FROM
    (<#= Table1 #>) Table1

<#+ string Table1 { get { return ToString(() => { #>
SELECT
    A,
    B
FROM
    Table1
<#+ });}} #>

G>> "Декомпозиция строк" надо записать.

AP>SELECT
AP>    A
AP>FROM
AP>    (<#= Table1 #>) Table1

AP><#+ string Table1 { get { return ToString(() => { #>
AP>SELECT
AP>    A,
AP>    B
AP>FROM
AP>    Table1
AP><#+ });}} #>
AP>

var query = GetQuery();
if(A)
{
    query = query.Where(...);
}
if(B)
{
    if(C)
    {
        query = SomeProcessQuery(query);
    }
    else
    {
        query = OtherProcessQuery(query);
    }
}

AP>SELECT
AP>    A
AP>FROM
AP>    (<#= Table1 #>) Table1

AP><#+ string Table1 { get { return ToString(() => { #>
AP>SELECT
AP>    A,
AP>    B
AP>FROM
AP>    Table1
AP><#+ });}} #>
AP>

SELECT
    A
FROM
    (<# Table1() #>) Table1

<#+ void Table1() { #>
SELECT
    A,
    B
FROM
    Table1
<#+ } #>

<# var query = GetQuery();
if(A)
{
    query = ToString(() => {#>
SELECT 
    *
FROM 
    (<#= query #>) T1
WHERE
    ...
<#    });
}
if(B)
{
    if(C)
    {
        query = SomeProcessQuery(query);
    }
    else
    {
        query = OtherProcessQuery(query);
    }
} #>

static void Main(string arg)
{
    ExecuteQuery(GetQueryText(bool.Parse(arg)))
}

static void ExecuteQuery(string queryText)
{
...
}

static string GetQueryText(bool condition)
{
    if (condition)
    {
        return "SELECT A FROM T1";
    }
    else
    {
        return "SELECT A FROM T2";
    }
}

static void Main(string arg)
{
    ExecuteQuery(GetQueryText(bool.Parse(arg)))
}

static void ExecuteQuery(string queryText)
{
...
}

static string GetQueryText(bool condition)
{
    return new StringBuilder().AppendFormat("SELECT A FROM {0}", condition ? "T1" : "T2").ToString();
}