不固定参数的存储过程实现代码

时间:2020-12-16 人气:0

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：

复制代码代码如下:

 
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：

复制代码代码如下:

 
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：

复制代码代码如下:

 
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：

试试这样会不会快一些

复制代码代码如下:

 
SELECT SUM(CASE WHEN UnitPrice < 10 THEN 1 ELSE 0 END) '<$10', 
SUM(CASE WHEN UnitPrice BETWEEN 11 AND 20 THEN 1 ELSE 0 END) '$11-$20', 
SUM(CASE WHEN UnitPrice BETWEEN 21 AND 30 THEN 1 ELSE 0 END) '$21-$30', 
... 
SUM(CASE WHEN UnitPrice > 50 THEN 1 ELSE 0 END) '>$10' 
FROM dbo.Products 
WHERE ProductID IN(SELECT sp FROM dbo.GetSplitFieldsByString(@ids,',')) 

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