Question

我有这个游标（SQL SERVER 2008 R2）来找出每个产品属于哪个类别。但有一个问题是某些产品没有任何子类别和类别（产品可以加入子类别，而saubcategory可以加入类别）。所以所有产品都不属于同类产品。我想知道如何在这个游标中放置一个IF / ELSE语句，如果Production.ProductCategory = null，那么它将把它放在另一个类别'No category！'中。任何想法怎么??

--** Force to use advantureworks
USE AdventureWorks
GO

--** Declaring Category Cursor variables
--** catName is for the CATEGORY NAME and count is a counter to count the row of output
DECLARE @catName VARCHAR(20), @count int

--** Declaring Category Cursor it self(to loop on categiries) and the SELECT statement
DECLARE catCursor CURSOR FOR
SELECT Production.ProductCategory.Name FROM Production.ProductCategory

--** Opening cursor and fetching data from it
OPEN catCursor
FETCH NEXT FROM  catCursor INTO @catName

--** Starting the loop in curser and filling the data
SET @count = 1
WHILE(@@FETCH_STATUS = 0)
BEGIN


PRINT N'Category Name: ' + CAST(@catName AS NVARCHAR) 
PRINT N'Description: No description'
PRINT N'Product List: '
PRINT N'Row NO.  Product ID     Product   Name                                  Unit Price($)   Is Top 10'
PRINT '======   ==========      =====================           ==========      ========='

--** Second cursor for products start here
--** Declaring Product Cursor variables
--** prodID, prodName and prodUnitPrice are what assignment wants from us
DECLARE @prodID INT, @prodName VARCHAR(30), @prodUnitPrice VARCHAR(20), @isTopTen VARCHAR (3)

--** Declaring Product Cursor it self(to loop on all products) and the SELECT statement
DECLARE prodCursor CURSOR FOR

--** HERE THERE MIGHT BE A CORRET SELEC STATEMENT WHICH STILL I DON'T KNOW WHAT IS !!!
--** I'VE WRITTEN SOMETHING WHICH IS NOT CORRECT BUT I PUT IT HERE IN COMMENTS:

SELECT DISTINCT A.ProductID, A.Name,  SUM(ISNULL(SOD.UnitPrice,0))/COUNT(*) 'Unit Price' , A.InTopTen 
FROM 
(SELECT P.ProductID, P.Name,PC.Name catName,
CASE WHEN X.ProductID IS NULL THEN 'NO' ELSE 'YES' END AS InTopTen
FROM Production.Product P 
LEFT JOIN Production.ProductSubcategory PSC ON P.ProductSubcategoryID = PSC.ProductSubcategoryID
LEFT JOIN Production.ProductCategory PC ON PSC.ProductCategoryID = PC.ProductCategoryID
LEFT JOIN
    (
        SELECT TOP 10 ProductID FROM Sales.SalesOrderDetail SOD
        GROUP BY ProductID
        ORDER BY COUNT(*) DESC
    ) X
ON X.ProductID = P.ProductID) A LEFT JOIN Sales.SalesOrderDetail SOD ON A.ProductID = SOD.ProductID
WHERE A.catName = CAST(@catName AS NVARCHAR)
GROUP BY A.ProductID , A.Name, A.InTopTen
ORDER BY A.ProductID

--** Opening cursor and fetching data from it
OPEN prodCursor 
FETCH NEXT FROM prodCursor INTO @prodID , @prodName , @prodUnitPrice , @isTopTen

--** Starting the loop in curser and filling the data
WHILE(@@FETCH_STATUS = 0)
BEGIN
PRINT CAST(@count AS NVARCHAR) 
+'       '+ CAST(@prodID AS NVARCHAR)
+'          '+ CAST(@prodName AS NVARCHAR)
+'                  ' + CAST(@prodUnitPrice AS NVARCHAR)
+'          ' + CAST(@isTopTen AS NVARCHAR)
SET @count = @count+1

--** Fetching next data from product cursor
FETCH NEXT FROM prodCursor INTO @prodID , @prodName , @prodUnitPrice , @IsTopTen

--** End of product cursor
END
CLOSE prodCursor
DEALLOCATE prodCursor
--*******************               

PRINT '===================================================================================='

--** Fetching next data from category cursor
FETCH NEXT FROM catCursor INTO @catName

--** End of category cursor
END
CLOSE catCursor
DEALLOCATE catCursor

 --=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=* END OF QUERY =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*

Answer 1

尝试使用：

DECLARE catCursor CURSOR FOR
SELECT Production.ProductCategory.Name FROM Production.ProductCategory
UNION ALL
SELECT 'No Category'

然后将您的WHERE子句更改为

WHERE ISNULL(A.catName, 'No Category') = CAST(@catName AS NVARCHAR)

如果游标值为null，则将if更改为值

1 个答案: