invalid：聚合函数或GROUP BY子句

Question

Hey guys I can't seem to figure out what I'm doing wrong here. I'm quite new to SQL so I can't wrap my head around this. Any help would be great!

SELECT PC.Name AS [ProductCategoryName]   
,      MIN(PCH.StandardCost) AS MinStandardCost
,      AVG(PCH.StandardCost) AS AverageStandardCost
,      MAX(PCH.StandardCost) AS MaxStandardCost 
FROM    ProductCategory PC
INNER JOIN    Product P ON (PC.ProductCategoryID = P.ProductCategoryID)
INNER JOIN    ProductCostHistory PCH ON ( P.ProductID = PCH.ProductID)
WHERE PC.Name LIKE '%Bike%'

Answer 1

You forgot the group by clause:

SELECT PC.Name AS [ProductCategoryName]   
,      MIN(PCH.StandardCost) AS MinStandardCost
,      AVG(PCH.StandardCost) AS AverageStandardCost
,      MAX(PCH.StandardCost) AS MaxStandardCost 
FROM    ProductCategory PC
INNER JOIN    Product P ON (PC.ProductCategoryID = P.ProductCategoryID)
INNER JOIN    ProductCostHistory PCH ON ( P.ProductID = PCH.ProductID)
WHERE PC.Name LIKE '%Bike%'
group by PC.NAME