Question

我有三个表：供应商，零件和类型。我需要加入所有这些，同时在三个表中区分具有相同名称的列（例如，“id”）。我想成功运行此查询：

CREATE VIEW Everything AS
SELECT Suppliers.name as supplier, 
       Parts.id, 
       Parts.description, 
       Types.typedesc as type
FROM Suppliers JOIN (Parts JOIN Types ON Parts.type_id = Types.id)
ON Suppliers.id = Parts.supplier_id;

我的DBMS（sqlite）抱怨“没有这样的列（Parts.id）”。我想在JOIN完成后会忘记表名，但是我怎样才能引用属于表id的列Parts？

Answer 1

您的ANSI-92 JOIN语法不正确 - 使用：

CREATE VIEW Everything AS
  SELECT Suppliers.name as supplier, 
         Parts.id, 
         Parts.description, 
         Types.typedesc as type
    FROM Suppliers 
    JOIN Parts ON Suppliers.id = Parts.supplier_id
    JOIN Types ON Parts.type_id = Types.id

Answer 2

只要您根据表Alias.Field名称对连接进行限定，就应该没有问题......例如

CREATE VIEW Everything AS 
      SELECT 
            Suppliers.name as supplier, 
            Parts.id, 
            Parts.description, 
            Types.typedesc as type 
         FROM 
            Suppliers,
            Parts,
            Types
         WHERE
                Supplier.ID = Parts.Supplier_ID
            AND Parts.Type_ID = Types.ID
         ORDER BY
            (whatever columns)

嵌套连接隐藏表名

2 个答案: