MySQL查詢問題

Question

我有4個表

Table: Category 
    CategoryID (int) 
    Name (varchar) 
Table: Products 
    ProductID (int) 
    CategoryID (int) 
    Name (varchar) 
    Description (text) 
Table: Sales 
    SalesID (int) 
    ProductID (int) 
Table: Links 
    LinkID (int) 
    ProductID (int) 

現在我需要顯示的數據爲：我怎樣才能做到這一點

CategoryName  Total Products  Total Sales  Total Links 
    ABC    5     12   50 
    XYZ    12     26   10 

，可在單個查詢

幫助表示讚賞

謝謝

Answer 1

SELECT c.Name AS "CategoryName", COUNT(p.ProductID) AS "TotalProducts", COUNT(s.SalesID) AS "TotalSales", COUNT(l.LinkID) AS "TotalLinks" 
FROM Category c 
INNER JOIN Products p ON p.CategoryID = c.CategoryID 
INNER JOIN Sales s ON s.ProductID = p.ProductID 
INNER JOIN Links l ON l.ProductID = s.ProductID; 

我不知道如何將數據看起來像，但你可能需要添加一個GROUP BY的地方，如果你有重複或可選ORDER BY如果需要排序在任何列