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當有8000行要處理時，此報告大約需要16秒。現在有50000行，報告需要2:30分鐘。SQL查詢優化
這是我第一次通過這個，客戶需要它，所以我按照需要完成的邏輯順序編寫了這段代碼，但沒有考慮優化。
現在隨着數據的增加，報告花費的時間越來越長，我需要再看看這個並優化它。我正在考慮索引視圖，表函數等
我認爲最大的瓶頸是循環通過臨時表，使4選擇語句，並更新臨時表... 50,000次。
我想我可以將所有這一切壓縮成一個大的SELECT，或者（a）4個連接到同一個表以獲得4個狀態，但是我不知道如何獲得TOP 1，或者我可以嘗試（b）使用嵌套子查詢，但與當前代碼相比，這兩者看起來都很混亂。我不希望任何人爲我編寫代碼，但是如果一些SQL專家可以仔細閱讀這段代碼，並告訴我任何明顯的低效率和替代方法，或者提高速度的方法，或者我應該使用的技術，而不是，將不勝感激。
PS：假設這個數據庫的大部分是規範化的，但設計不好，而且我無法添加索引。我基本上必須像現在一樣使用它。
代碼說（小於）我必須替換「小於」符號，因爲它裁剪了我的一些代碼。
謝謝！
CREATE PROCEDURE RptCollectionAccountStatusReport AS
SET NOCOUNT ON;
DECLARE @Accounts TABLE
(
[AccountKey] INT IDENTITY(1,1) NOT NULL,
[ManagementCompany] NVARCHAR(50),
[Association] NVARCHAR(100),
[AccountNo] INT UNIQUE,
[StreetAddress] NVARCHAR(65),
[State] NVARCHAR(50),
[PrimaryStatus] NVARCHAR(100),
[PrimaryStatusDate] SMALLDATETIME,
[PrimaryDaysRemaining] INT,
[SecondaryStatus] NVARCHAR(100),
[SecondaryStatusDate] SMALLDATETIME,
[SecondaryDaysRemaining] INT,
[TertiaryStatus] NVARCHAR(100),
[TertiaryStatusDate] SMALLDATETIME,
[TertiaryDaysRemaining] INT,
[ExternalStatus] NVARCHAR(100),
[ExternalStatusDate] SMALLDATETIME,
[ExternalDaysRemaining] INT
);
INSERT INTO
@Accounts (
[ManagementCompany],
[Association],
[AccountNo],
[StreetAddress],
[State])
SELECT
mc.Name AS [ManagementCompany],
a.LegalName AS [Association],
c.CollectionKey AS [AccountNo],
u.StreetNumber + ' ' + u.StreetName AS [StreetAddress],
CASE WHEN c.InheritedAccount = 1 THEN 'ZZ' ELSE u.State END AS [State]
FROM
ManagementCompany mc WITH (NOLOCK)
JOIN
Association a WITH (NOLOCK) ON a.ManagementCompanyKey = mc.ManagementCompanyKey
JOIN
Unit u WITH (NOLOCK) ON u.AssociationKey = a.AssociationKey
JOIN
Collection c WITH (NOLOCK) ON c.UnitKey = u.UnitKey
WHERE
c.Closed IS NULL;
DECLARE @MaxAccountKey INT;
SELECT @MaxAccountKey = MAX([AccountKey]) FROM @Accounts;
DECLARE @index INT;
SET @index = 1;
WHILE @index (less than) @MaxAccountKey BEGIN
DECLARE @CollectionKey INT;
SELECT @CollectionKey = [AccountNo] FROM @Accounts WHERE [AccountKey] = @index;
DECLARE @PrimaryStatus NVARCHAR(100) = NULL;
DECLARE @PrimaryStatusDate SMALLDATETIME = NULL;
DECLARE @PrimaryDaysRemaining INT = NULL;
DECLARE @SecondaryStatus NVARCHAR(100) = NULL;
DECLARE @SecondaryStatusDate SMALLDATETIME = NULL;
DECLARE @SecondaryDaysRemaining INT = NULL;
DECLARE @TertiaryStatus NVARCHAR(100) = NULL;
DECLARE @TertiaryStatusDate SMALLDATETIME = NULL;
DECLARE @TertiaryDaysRemaining INT = NULL;
DECLARE @ExternalStatus NVARCHAR(100) = NULL;
DECLARE @ExternalStatusDate SMALLDATETIME = NULL;
DECLARE @ExternalDaysRemaining INT = NULL;
SELECT TOP 1
@PrimaryStatus = a.StatusName, @PrimaryStatusDate = c.StatusDate, @PrimaryDaysRemaining = c.DaysRemaining
FROM CollectionAccountStatus c WITH (NOLOCK) JOIN AccountStatus a WITH (NOLOCK) ON c.AccountStatusKey = a.AccountStatusKey
WHERE c.CollectionKey = @CollectionKey AND a.StatusType = 'Primary Status' AND a.StatusName 'Cleared'
ORDER BY c.sysCreated DESC;
SELECT TOP 1
@SecondaryStatus = a.StatusName, @SecondaryStatusDate = c.StatusDate, @SecondaryDaysRemaining = c.DaysRemaining
FROM CollectionAccountStatus c WITH (NOLOCK) JOIN AccountStatus a WITH (NOLOCK) ON c.AccountStatusKey = a.AccountStatusKey
WHERE c.CollectionKey = @CollectionKey AND a.StatusType = 'Secondary Status' AND a.StatusName 'Cleared'
ORDER BY c.sysCreated DESC;
SELECT TOP 1
@TertiaryStatus = a.StatusName, @TertiaryStatusDate = c.StatusDate, @TertiaryDaysRemaining = c.DaysRemaining
FROM CollectionAccountStatus c WITH (NOLOCK) JOIN AccountStatus a WITH (NOLOCK) ON c.AccountStatusKey = a.AccountStatusKey
WHERE c.CollectionKey = @CollectionKey AND a.StatusType = 'Tertiary Status' AND a.StatusName 'Cleared'
ORDER BY c.sysCreated DESC;
SELECT TOP 1
@ExternalStatus = a.StatusName, @ExternalStatusDate = c.StatusDate, @ExternalDaysRemaining = c.DaysRemaining
FROM CollectionAccountStatus c WITH (NOLOCK) JOIN AccountStatus a WITH (NOLOCK) ON c.AccountStatusKey = a.AccountStatusKey
WHERE c.CollectionKey = @CollectionKey AND a.StatusType = 'External Status' AND a.StatusName 'Cleared'
ORDER BY c.sysCreated DESC;
UPDATE
@Accounts
SET
[PrimaryStatus] = @PrimaryStatus,
[PrimaryStatusDate] = @PrimaryStatusDate,
[PrimaryDaysRemaining] = @PrimaryDaysRemaining,
[SecondaryStatus] = @SecondaryStatus,
[SecondaryStatusDate] = @SecondaryStatusDate,
[SecondaryDaysRemaining] = @SecondaryDaysRemaining,
[TertiaryStatus] = @TertiaryStatus,
[TertiaryStatusDate] = @TertiaryStatusDate,
[TertiaryDaysRemaining] = @TertiaryDaysRemaining,
[ExternalStatus] = @ExternalStatus,
[ExternalStatusDate] = @ExternalStatusDate,
[ExternalDaysRemaining] = @ExternalDaysRemaining
WHERE
[AccountNo] = @CollectionKey;
SET @index = @index + 1;
END;
SELECT
[ManagementCompany],
[Association],
[AccountNo],
[StreetAddress],
[State],
[PrimaryStatus],
CONVERT(VARCHAR, [PrimaryStatusDate], 101) AS [PrimaryStatusDate],
[PrimaryDaysRemaining],
[SecondaryStatus],
CONVERT(VARCHAR, [SecondaryStatusDate], 101) AS [SecondaryStatusDate],
[SecondaryDaysRemaining],
[TertiaryStatus],
CONVERT(VARCHAR, [TertiaryStatusDate], 101) AS [TertiaryStatusDate],
[TertiaryDaysRemaining],
[ExternalStatus],
CONVERT(VARCHAR, [ExternalStatusDate], 101) AS [ExternalStatusDate],
[ExternalDaysRemaining]
FROM
@Accounts
ORDER BY
[ManagementCompany],
[Association],
[StreetAddress]
ASC;
您正在使用什麼版本的SQL Server？ – Lamak 2011-02-07 17:32:03
SQL 2008 R2是該版本。 – Blackcoil 2011-02-07 17:35:16