Warum CTE (Common Table Expressions) in einigen Fällen Abfragen im Vergleich zu temporären Tabellen in SQL Server verlangsamen

Ich habe mehrere Fälle, in denen meine komplexe CTE (Common Table Expressions) zehnmal langsamer ist als die gleichen Abfragen, die die temporären Tabellen in SQL Server verwenden.

Meine Frage hier ist, wie SQL Server die CTE-Abfragen verarbeitet. Es sieht so aus, als würde sie versuchen, alle getrennten Abfragen zusammenzufügen, anstatt die Ergebnisse jeder einzelnen zu speichern und dann die folgenden auszuführen. Das könnte der Grund sein, warum es bei der Verwendung temporärer Tabellen so schneller ist.

Zum Beispiel:

Abfrage 1 : mit Common Table Expression:

;WITH Orders AS
(
    SELECT
        ma.MasterAccountId,
        IIF(r.FinalisedDate IS NULL, 1, 0)) [Status]
    FROM 
        MasterAccount ma
    INNER JOIN 
        task.tblAccounts a ON a.AccountNumber = ma.TaskAccountId 
                           AND a.IsActive = 1
    LEFT OUTER JOIN 
        task.tblRequisitions r ON r.AccountNumber = a.AccountNumber 
    WHERE 
        ma.IsActive = 1
        AND CAST(r.BatchDateTime AS DATE) BETWEEN @fromDate AND @toDate
        AND r.BatchNumber > 0
),
StockAvailability AS
(
    SELECT sa.AccountNumber,
           sa.RequisitionNumber,
           sa.RequisitionDate,
           sa.Lines,
           sa.HasStock,
           sa.NoStock,
           CASE WHEN sa.Lines = 0 THEN 'Empty'
                WHEN sa.HasStock = 0 THEN 'None'
                WHEN (sa.Lines > 0 AND sa.Lines > sa.HasStock) THEN 'Partial'
                WHEN (sa.Lines > 0 AND sa.Lines <= sa.HasStock) THEN 'Full'
            END AS [Status]
    FROM
    (
        SELECT
                r.AccountNumber,
                r.RequisitionNumber,
                r.RequisitionDate,
                COUNT(rl.ProductNumber) Lines,
                SUM(IIF(ISNULL(psoh.AvailableStock, 0) >= ISNULL(rl.Quantity, 0), 1, 0)) AS HasStock,
                SUM(IIF(ISNULL(psoh.AvailableStock, 0) < ISNULL(rl.Quantity, 0), 1, 0)) AS NoStock

        FROM task.tblrequisitions r 
        INNER JOIN task.tblRequisitionLines rl ON rl.RequisitionNumber = r.RequisitionNumber
        LEFT JOIN ProductStockOnHandSummary psoh ON psoh.ProductNumber = rl.ProductNumber

        WHERE dbo.fn_RemoveUnitPrefix(r.BatchNumber) = 0
          AND r.UnitId = 1
          AND r.FinalisedDate IS NULL
          AND r.RequisitionStatus = 1 
          AND r.TransactionTypeNumber = 301 
        GROUP BY r.AccountNumber, r.RequisitionNumber, r.RequisitionDate
    ) AS sa
),
Available AS
(
    SELECT  ma.MasterAccountId,
            SUM(IIF(ma.IsPartialStock = 1,  CASE WHEN sa.[Status] IN ('Full', 'Partial') THEN 1 ELSE 0 END, 
                                            CASE WHEN sa.[Status] = 'Full' THEN 1 ELSE 0 END)) AS AvailableStock,
            SUM(IIF(sa.[Status] IN ('Full', 'Partial', 'None'), 1, 0))  AS OrdersAnyStock, 

            SUM(IIF(sa.RequisitionDate < dbo.TicksToTime(ma.DailyOrderCutOffTime, @toDate),
                    IIF(ma.IsPartialStock = 1,  CASE WHEN sa.[Status] IN ('Full', 'Partial') THEN 1 ELSE 0 END, 
                                                CASE WHEN sa.[Status] = 'Full' THEN 1 ELSE 0 END), 0)) AS AvailableBeforeCutOff                             
    FROM MasterAccount ma
    INNER JOIN StockAvailability sa ON sa.AccountNumber = ma.TaskAccountId
    GROUP BY ma.MasterAccountId, ma.IsPartialStock
),
Totals AS
(
    SELECT 
        o.MasterAccountId,
        COUNT(o.MasterAccountId) AS BatchedOrders
    FROM Orders o
    GROUP BY o.MasterAccountId
)
SELECT a.MasterAccountId,
       ISNULL(t.BatchedOrders, 0) BatchedOrders,
       ISNULL(t.PendingOrders, 0) PendingOrders,
       ISNULL(av.AvailableStock, 0) AvailableOrders,
       ISNULL(av.AvailableBeforeCutOff, 0) AvailableCutOff,
       ISNULL(av.OrdersAnyStock, 0) AllOrders
FROM MasterAccount a
LEFT OUTER JOIN Available av ON av.MasterAccountId = a.MasterAccountId
LEFT OUTER JOIN Totals t ON t.MasterAccountId = a.MasterAccountId
WHERE a.IsActive = 1

Abfrage 2 : temporäre Tabellen verwenden:

DROP TABLE IF EXISTS #Orders

CREATE TABLE #Orders (MasterAccountId int, [Status] int);

INSERT INTO #Orders
SELECT
    ma.MasterAccountId,
    dbo.fn_GetBatchPickingStatus(ma.BatchPickingOnHold,
                                    iif(r.GroupNumber > 0, 1, 0),
                                    iif(r.FinalisedDate is null, 1, 0)) [Status]
FROM MasterAccount ma (nolock)
INNER JOIN wh3.dbo.tblAccounts a (nolock) on a.AccountNumber = dbo.fn_RemoveUnitPrefix(ma.TaskAccountId) and a.IsActive = 1
LEFT OUTER JOIN wh3.dbo.tblRequisitions r (nolock) on r.AccountNumber = a.AccountNumber 
WHERE cast(r.BatchDateTime as date) between @fromDate and @toDate
    AND r.BatchNumber > 0
    AND ma.IsActive = 1

DROP TABLE IF EXISTS #StockAvailability
Create Table #StockAvailability (AccountNumber int, RequisitionNumber int, RequisitionDate datetime, Lines int, HasStock int, NoStock int);
Insert Into #StockAvailability
SELECT
        r.AccountNumber,
        r.RequisitionNumber,
        r.RequisitionDate,
        COUNT(rl.ProductNumber) Lines,
        SUM(IIF(ISNULL(psoh.AvailableStock, 0) >= ISNULL(rl.Quantity, 0), 1, 0)) AS HasStock,
        SUM(IIF(ISNULL(psoh.AvailableStock, 0) < ISNULL(rl.Quantity, 0), 1, 0)) AS NoStock

FROM WH3.dbo.tblrequisitions r (nolock)
INNER JOIN WH3.dbo.tblRequisitionLines rl (nolock) ON rl.RequisitionNumber = r.RequisitionNumber
LEFT JOIN ProductStockOnHandSummary psoh (nolock) ON psoh.ProductNumber = rl.ProductNumber -- Joined with View          
WHERE r.BatchNumber = 0
    AND r.FinalisedDate is null
    AND r.RequisitionStatus = 1 
    AND r.TransactionTypeNumber = 301 
GROUP BY r.AccountNumber, r.RequisitionNumber, r.RequisitionDate

DROP TABLE IF EXISTS #StockAvailability2
Create Table #StockAvailability2 (AccountNumber int, RequisitionNumber int, RequisitionDate datetime, Lines int, HasStock int, NoStock int, [Status] nvarchar(7));
Insert Into #StockAvailability2
SELECT sa.AccountNumber,
        sa.RequisitionNumber,
        sa.RequisitionDate,
        sa.Lines,
        sa.HasStock,
        sa.NoStock,
        CASE WHEN sa.Lines = 0 THEN 'Empty'
            WHEN sa.HasStock = 0 THEN 'None'
            WHEN (sa.Lines > 0 AND sa.Lines > sa.HasStock) THEN 'Partial'
            WHEN (sa.Lines > 0 AND sa.Lines <= sa.HasStock) THEN 'Full'
        END AS [Status]
FROM #StockAvailability sa

DROP TABLE IF EXISTS #Available
Create Table #Available (MasterAccountId int, AvailableStock int, OrdersAnyStock int, AvailableBeforeCutOff int);
INSERT INTO #Available
SELECT  ma.MasterAccountId,
        SUM(IIF(ma.IsPartialStock = 1,  CASE WHEN sa.[Status] IN ('Full', 'Partial') THEN 1 ELSE 0 END, 
                                        CASE WHEN sa.[Status] = 'Full' THEN 1 ELSE 0 END)) AS AvailableStock,
        SUM(IIF(sa.[Status] IN ('Full', 'Partial', 'None'), 1, 0))  AS OrdersAnyStock, 

        SUM(IIF(sa.RequisitionDate < dbo.TicksToTime(ma.DailyOrderCutOffTime, @toDate),
                IIF(ma.IsPartialStock = 1,  CASE WHEN sa.[Status] IN ('Full', 'Partial') THEN 1 ELSE 0 END, 
                                            CASE WHEN sa.[Status] = 'Full' THEN 1 ELSE 0 END), 0)) AS AvailableBeforeCutOff                             
FROM MasterAccount ma (NOLOCK)
INNER JOIN #StockAvailability2 sa ON sa.AccountNumber = dbo.fn_RemoveUnitPrefix(ma.TaskAccountId)
GROUP BY ma.MasterAccountId, ma.IsPartialStock


;WITH Totals AS
(
    SELECT 
        o.MasterAccountId,
        COUNT(o.MasterAccountId) AS BatchedOrders,
        SUM(IIF(o.[Status] IN (0,1,2), 1, 0)) PendingOrders
    FROM #Orders o (NOLOCK)
    GROUP BY o.MasterAccountId
)
SELECT a.MasterAccountId,
       ISNULL(t.BatchedOrders, 0) BatchedOrders,
       ISNULL(t.PendingOrders, 0) PendingOrders,
       ISNULL(av.AvailableStock, 0) AvailableOrders,
       ISNULL(av.AvailableBeforeCutOff, 0) AvailableCutOff,
       ISNULL(av.OrdersAnyStock, 0) AllOrders
FROM MasterAccount a (NOLOCK)
LEFT OUTER JOIN #Available av (NOLOCK) ON av.MasterAccountId = a.MasterAccountId
LEFT OUTER JOIN Totals t (NOLOCK) ON t.MasterAccountId = a.MasterAccountId
WHERE a.IsActive = 1