join
person表
person表.png
orders表
orders表.png
谁订购了产品，并且他们订购了什么产品？
SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo
FROM Persons, Orders
WHERE Persons.Id_P = Orders.Id_P
内链接
列出所有人的定购
SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo
FROM Persons
INNER JOIN Orders
ON Persons.Id_P=Orders.Id_P
ORDER BY Persons.LastName
union
SELECT column_name(s) FROM table_name1
UNION
SELECT column_name(s) FROM table_name2
插入新表
SELECT *
INTO Persons_backup
FROM Persons
创建视图
CREATE VIEW [Current Product List] AS
SELECT ProductID,ProductName
FROM Products
WHERE Discontinued=No
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