存储过程新手疑惑~望高手帮忙解答下~

[davidcoffee]

USE AdventureWorks;
GO
IF OBJECT_ID ( 'Production.usp_GetList', 'P' ) IS NOT NULL
DROP PROCEDURE Production.usp_GetList;
GO
CREATE PROCEDURE Production.usp_GetList @product varchar(40)
, @maxprice money
, @compareprice money OUTPUT
, @listprice money OUT
AS
SELECT p.name AS Product, p.ListPrice AS 'List Price'
FROM Production.Product p
JOIN Production.ProductSubcategory s
ON p.ProductSubcategoryID = s.ProductSubcategoryID
WHERE s.name LIKE @product AND p.ListPrice < @maxprice;
-- Populate the output variable @listprice.
SET @listprice = (SELECT MAX(p.ListPrice)
FROM Production.Product p
JOIN Production.ProductSubcategory s
ON p.ProductSubcategoryID = s.ProductSubcategoryID
WHERE s.name LIKE @product AND p.ListPrice < @maxprice);
-- Populate the output variable @compareprice.
SET @compareprice = @maxprice;
GO
该段存储过程是返回其价格不超过指定金额的产品列表
网上百度了下说OUTPUT是输出参数，OUT是普通输入参数，所以不明白如果OUT是输入参数那@product， @maxprice money
这两个输入参数和有OUT声明的有什么区别吗，还有就是SET @listprice 取得产品价格中的最大值是做什么用的，因为指定金额不是用 @maxprice money传入进来的吗~麻烦高手解惑~3Q~

[永生天地]

OUTPUT 是关键字
out是不对的吧

[davidcoffee]

[Quote=引用 1 楼 xys_777 的回复:]
OUTPUT 是关键字
out是不对的吧
[/Quote]
那输入参数就是不用out 直接@param_name这种就可以了吗？

[Linares]

真忽悠，看看MSDN，OUT/OUTPUT是等价的

CREATE { PROC | PROCEDURE } [schema_name.] procedure_name [ ; number ]
[ { @parameter [ type_schema_name. ] data_type }
[ VARYING ] [ = default ] [ OUT | OUTPUT ] [READONLY]
] [ ,...n ]

SET @listprice 取得产品价格中的最大值是做什么用
@maxprice 是上限，不是实际的最大值

内事百度
外事谷歌

[Rotel-刘志东]

USE AdventureWorks;
GO
IF OBJECT_ID ( 'Production.usp_GetList', 'P' ) IS NOT NULL  
  DROP PROCEDURE Production.usp_GetList;
GO
CREATE PROCEDURE Production.usp_GetList @product varchar(40)  
  , @maxprice money  
  , @compareprice money OUTPUT
  , @listprice money OUT ---out不对
AS
  SELECT p.name AS Product, p.ListPrice AS 'List Price'
  FROM Production.Product p
  JOIN Production.ProductSubcategory s  
  ON p.ProductSubcategoryID = s.ProductSubcategoryID
  WHERE s.name LIKE @product AND p.ListPrice < @maxprice;
-- Populate the output variable @listprice.
SET @listprice = (SELECT MAX(p.ListPrice)
  FROM Production.Product p
  JOIN Production.ProductSubcategory s  
  ON p.ProductSubcategoryID = s.ProductSubcategoryID
  WHERE s.name LIKE @product AND p.ListPrice < @maxprice);
-- Populate the output variable @compareprice.
SET @compareprice = @maxprice;
GO

[davidcoffee]

[Quote=引用 3 楼 linares 的回复:]
真忽悠，看看MSDN，OUT/OUTPUT是等价的

CREATE { PROC | PROCEDURE } [schema_name.] procedure_name [ ; number ]
[ { @parameter [ type_schema_name. ] data_type }
[ VARYING ] [ = default ] [ OUT | OUTPUT ] ……
[/Quote]
哦got it~散分了~