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第12课 联结表

  • 12.1 联结
    • 12.1.1 关系表
    • 12.1.2 为什么使用联结
  • 12.2 创建联结
    • SELECT vend_name, prod_name, prod_price
    • FROM Vendors, Products
    • WHERE Vendors.vend_id = Products.vend_id;
  • 12.2.1 WHERE 子句的重要性
  • 12.2.2 内连接
    • SELECT vend_name, prod_name, prod_price
    • FROM Vendors INNER JOIN Products
    • ON Vendors.vend_id = Products.vend_id;
  • 12.2.3 联结多个表
    • SELECT prod_name, vend_name, prod_price, quantity
    • FROM OrderItems, Products, Vendors
    • WHERE Products.vend_id = Vendors.vend_id
    • AND OrderItems.prod_id = Products.prod_id
    • AND order_num = 20007;
  • 12.3 小结





posted on 2019-01-19 01:21  XuCodeX  阅读(91)  评论(0)    收藏  举报

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