SQL Server 完成數字幫助表實例代碼。本站提示廣大學習愛好者：（SQL Server 完成數字幫助表實例代碼）文章只能為提供參考，不一定能成為您想要的結果。以下是SQL Server 完成數字幫助表實例代碼正文
數字幫助表是一個持續整數的數列，平日用來完成多種分歧的查詢義務。年夜多分兩類：足夠年夜物理數字表和表函數，前者可以稱為靜態的，後者可以稱為靜態且按需臨盆。
物理數字表
物理數字表平日存在一個物理表，表記載絕對足夠年夜，相干的T-SQL代碼以下：
IF OBJECT_ID(N'dbo.Nums', 'U') IS NOT NULL
BEGIN
DROP TABLE dbo.Nums;
END
GO
CREATE TABLE dbo.Nums
(
Num INT NOT NULL,
CONSTRAINT PK_U_CL_Nums_Num PRIMARY KEY CLUSTERED
(
Num ASC
)
);
GO
INSERT INTO dbo.Nums (Num)
SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS RowNum
FROM master.dbo.spt_values;
GO
留意：若何填充物理數字表的辦法許多，為了演示感化應用了一種。
測試的T-SQL代碼以下：
1 SELECT Num 2 FROM dbo.Nums; 3 GO
履行後的查詢成果以下：
表函數
表函數完成應用穿插銜接和CTE，SQL Server 2005和以上版本的T-SQL代碼以下：
IF OBJECT_ID(N'dbo.ufn_GetNums', N'IF') IS NOT NULL
BEGIN
DROP TABLE dbo.ufn_GetNums;
END
GO
--==================================
-- 功效: 獲得指定規模的數字數列
-- 解釋: 穿插最初層級的CTE獲得的數據行：在L級（從0開端計數）獲得的行的總數為2^2^L。
-- 例如：在5級就會獲得4 294 967 596行。5級的CTE供給了跨越40億的行。
-- 作者: XXX
-- 創立: yyyy-MM-dd
-- 修正: yyyy-MM-dd XXX 修正內容描寫
--==================================
CREATE FUNCTION dbo.ufn_GetNums
(
@bintLow BIGINT,
@bintHigh BIGINT
) RETURNS TABLE
AS
RETURN
WITH
L0 AS (SELECT c FROM (VALUES(1), (1)) AS LO(c)),
L1 AS (SELECT 1 AS c FROM L0 AS T CROSS JOIN L0 AS T2),
L2 AS (SELECT 1 AS c FROM L1 AS T CROSS JOIN L1 AS T2),
L3 AS (SELECT 1 AS c FROM L2 AS T CROSS JOIN L2 AS T2),
L4 AS (SELECT 1 AS c FROM L3 AS T CROSS JOIN L3 AS T2),
L5 AS (SELECT 1 AS c FROM L4 AS T CROSS JOIN L4 AS T2),
Nums AS (SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS RowNum FROM L5)
SELECT TOP (@bintHigh - @bintLow + 1) @bintLow + RowNum - 1 AS Num
FROM Nums
ORDER BY RowNum ASC;
GO
SQL Server 2012增長了有關分頁的新特征，相干的T-SQL代碼以下:
IF OBJECT_ID(N'dbo.ufn_GetNums2', N'IF') IS NOT NULL
BEGIN
DROP TABLE dbo.ufn_GetNums2;
END
GO
--==================================
-- 功效: 獲得指定規模的數字數列
-- 解釋: 穿插最初層級的CTE獲得的數據行：在L級（從0開端計數）獲得的行的總數為2^2^L。
-- 例如：在5級就會獲得4 294 967 596行。5級的CTE供給了跨越40億的行。
-- 作者: XXX
-- 創立: yyyy-MM-dd
-- 修正: yyyy-MM-dd XXX 修正內容描寫
--==================================
CREATE FUNCTION dbo.ufn_GetNums2
(
@bintLow BIGINT,
@bintHigh BIGINT
) RETURNS TABLE
AS
RETURN
WITH
L0 AS (SELECT c FROM (VALUES(1), (1)) AS LO(c)),
L1 AS (SELECT 1 AS c FROM L0 AS T CROSS JOIN L0 AS T2),
L2 AS (SELECT 1 AS c FROM L1 AS T CROSS JOIN L1 AS T2),
L3 AS (SELECT 1 AS c FROM L2 AS T CROSS JOIN L2 AS T2),
L4 AS (SELECT 1 AS c FROM L3 AS T CROSS JOIN L3 AS T2),
L5 AS (SELECT 1 AS c FROM L4 AS T CROSS JOIN L4 AS T2),
Nums AS (SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS RowNum FROM L5)
SELECT @bintLow + RowNum - 1 AS Num
FROM Nums
ORDER BY RowNum ASC
OFFSET 0 ROWS FETCH FIRST @bintHigh - @bintLow + 1 ROWS ONLY;
GO
以函數ufn_GetNums為例，演示相干的後果。獲得指定規模的數字序列的T-SQL代碼以下：
SELECT Num FROM dbo.ufn_GetNums(11, 20); GO
履行後的查詢成果以下：
博友若有其他更好的處理計劃，也請不惜賜教，萬分感激。
參考清單列表
1、《Microsoft SQL Server 2012 High-Performance T-SQL Using Window Functions》 作者 Itzik Ben-Gan（美國）（SQL Server Inside 有關書本的作者）
感激浏覽，願望能贊助到年夜家，感謝年夜家對本站的支撐！
