全完是我个人理解.可能语言上有有错误....我也是才学SQL...
查询Produces表原始数据...但是需要得出品种名称..表中CategoryID字段所记录的数据是品种的编号..1SELECT ProductID, ProductName, SupplierID, CategoryID, QuantityPerUnit, UnitPrice, UnitsInStock, UnitsOnOrder, ReorderLevel, Discontinued,
2(SELECT CategoryName FROM Categories WHERE Categories.CategoryID = Products.CategoryID) as CategoryName
3 FROM Products
那么要通过品种编号ID得出品种名称.所以在主查询设置所需要查询字段的部分`加入子查询
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最后得出结果就会多出一个CategoryName表.`里面装的数据就是当前本条记录的产品品种名称.
完整的例子:
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SELECT ProductID, ProductName, SupplierID, CategoryID,
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QuantityPerUnit, UnitPrice, UnitsInStock, UnitsOnOrder, ReorderLevel, Discontinued,
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(SELECT CategoryName FROM Categories
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WHERE Categories.CategoryID = Products.CategoryID) as CategoryName,
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(SELECT CompanyName FROM Suppliers
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WHERE Suppliers.SupplierID = Products.SupplierID) as SupplierName
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FROM Products
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