[转载]不固定参数的存储过程-Mikel

[转载]不固定参数的存储过程 – KenshinCui’s Blog – 博客园.

我们知道存储过程是不支持不固定参数情况的（包括数组参数），可是有时候我们的参数又必须是不固定的，怎么办呢？我想此时不妨使用字符串参数来帮助我们解决这种情况，利用字符串分割的方法将一个参数分割成数个参数来解决。下面我们看一个例子：

假设现在给你一个产品信息列表（显示出各个商品的基本信息），现在我想要根据所选择商品进行统计（任意选择几种），例如统计出价格<10,11-20,21-30,31-40,41-50,50以上的商品个有多少个（姑且认为就统计这些）。此时如果使用存储过程就势必需要传入所选商品的id作为参数，但是id个数是不固定的。此时估计会有人这样写：

代码

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:        jianxin160
-- Create date: 2010.11.05
-- Description:    统计商品
-- =============================================
ALTER PROCEDURE StatProductInfo
(
    @ids VARCHAR(8000)
)
AS
BEGIN
    DECLARE @followingTen INT
    DECLARE @elevenToTwenty INT
    DECLARE @twentyOneToThirty INT
    DECLARE @thirtyOneToFourty INT
    DECLARE @fourtyOneToFifty INT
    DECLARE @fiftyOrMore INT
    
    SELECT @followingTen=COUNT(*)
    FROM dbo.Products 
    WHERE ProductID IN(@ids) AND UnitPrice<10
    
    SELECT @elevenToTwenty=COUNT(*)
    FROM dbo.Products 
    WHERE ProductID IN(@ids) AND UnitPrice BETWEEN 11 AND 20
    
    SELECT @twentyOneToThirty=COUNT(*)
    FROM dbo.Products 
    WHERE ProductID IN(@ids) AND UnitPrice BETWEEN 21 AND 30
    
    SELECT @thirtyOneToFourty=COUNT(*)
    FROM dbo.Products 
    WHERE ProductID IN(@ids) AND UnitPrice BETWEEN 31 AND 40
    
    SELECT @fourtyOneToFifty=COUNT(*)
    FROM dbo.Products 
    WHERE ProductID IN(@ids) AND UnitPrice BETWEEN 41 AND 50
    
    SELECT @fiftyOrMore=COUNT(*)
    FROM dbo.Products 
    WHERE ProductID IN(@ids) AND UnitPrice>50
    
    SELECT @followingTen AS '<$10',@elevenToTwenty AS '$11-$20',
    @twentyOneToThirty AS '$21-$30',@thirtyOneToFourty AS '$31-$40',
    @fourtyOneToFifty AS '$41-$50',@fiftyOrMore AS '>$50'
END
GO

其实如果你测试一下（例如：EXEC dbo . StatProductInfo ‘3,4,8,10,22’ ）是有问题的，SQL server认为这整个是一个参数，转换时出错。此时我们想一下如果这些字段在一个虚表中就容易操作多了，但是一般虚表是有其他表通过查询得到，现在根本无法查询又哪来的虚表呢？聪明的朋友或许已经想到可以使用”表值函数”。对，答案就是使用”表值函数”。我们知道”表值函数”可以返回一个”Table” 类型的变量（相当于一张虚表，存放于内存中），我们首先将字符串分割存放到”表值函数”的一个字段中，然后我们再从”表值函数”中查询就可以了（这个例子也是”表值函数”的一个典型应用）。具体SQL如下：

代码

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:        cmj
-- Create date: 2010.11.05
-- Description:    返回一个Table,只有一列，每一行的数据就是分割好的字符串
-- =============================================
CREATE FUNCTION GetSplitFieldsByString
(
    @toSplitString varchar(1000),
    @splitChar varchar(10)
)
RETURNS 
@tb TABLE(sp varchar(100))
AS
BEGIN
    DECLARE @i INT
    SET @toSplitString=RTRIM(LTRIM(@toSplitString))
    SET @i=CHARINDEX(@splitChar,@toSplitString)
    WHILE @i>0
        BEGIN
            INSERT @tb VALUES(LEFT(@toSplitString,@i-1))
            SET @toSplitString=RIGHT(@toSplitString,LEN(@toSplitString)-@i)        
            SET @i=CHARINDEX(@splitChar,@toSplitString)
        END
    IF LEN(@toSplitString)>0
        INSERT @tb VALUES(@toSplitString)
    RETURN 
END
GO

然后我们稍微修改一下存储过程：

代码

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:        jianxin160
-- Create date: 2010.11.05
-- Description:    统计商品
-- =============================================
ALTER PROCEDURE StatProductInfo
(
    @ids VARCHAR(8000)
)
AS
BEGIN
    DECLARE @followingTen INT
    DECLARE @elevenToTwenty INT
    DECLARE @twentyOneToThirty INT
    DECLARE @thirtyOneToFourty INT
    DECLARE @fourtyOneToFifty INT
    DECLARE @fiftyOrMore INT
    
    SELECT @followingTen=COUNT(*)
    FROM dbo.Products 
    WHERE ProductID IN(SELECT sp FROM dbo.GetSplitFieldsByString(@ids,',')) AND UnitPrice<10
    
    SELECT @elevenToTwenty=COUNT(*)
    FROM dbo.Products 
    WHERE ProductID IN(SELECT sp FROM dbo.GetSplitFieldsByString(@ids,',')) AND UnitPrice BETWEEN 11 AND 20
    
    SELECT @twentyOneToThirty=COUNT(*)
    FROM dbo.Products 
    WHERE ProductID IN(SELECT sp FROM dbo.GetSplitFieldsByString(@ids,',')) AND UnitPrice BETWEEN 21 AND 30
    
    SELECT @thirtyOneToFourty=COUNT(*)
    FROM dbo.Products 
    WHERE ProductID IN(SELECT sp FROM dbo.GetSplitFieldsByString(@ids,',')) AND UnitPrice BETWEEN 31 AND 40
    
    SELECT @fourtyOneToFifty=COUNT(*)
    FROM dbo.Products 
    WHERE ProductID IN(SELECT sp FROM dbo.GetSplitFieldsByString(@ids,',')) AND UnitPrice BETWEEN 41 AND 50
    
    SELECT @fiftyOrMore=COUNT(*)
    FROM dbo.Products 
    WHERE ProductID IN(SELECT sp FROM dbo.GetSplitFieldsByString(@ids,',')) AND UnitPrice>50
    
    SELECT @followingTen AS '<$10',@elevenToTwenty AS '$11-$20',@twentyOneToThirty AS '$21-$30',
    @thirtyOneToFourty AS '$31-$40',@fourtyOneToFifty AS '$41-$50',@fiftyOrMore AS '>$50'
END
GO

这样通过执行EXEC dbo . StatProductInfo ‘3,4,8,10,22’ 就可以得到想要的结果了：

[转载]不固定参数的存储过程

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