如何使用SQL Server选择其他表？

CREATE TABLE Users (
    UserID INT PRIMARY KEY,
    UserName NVARCHAR(50),
    UserEmail NVARCHAR(100)
);

CREATE TABLE Orders (
    OrderID INT PRIMARY KEY,
    UserID INT,
    ProductName NVARCHAR(100),
    OrderDate DATETIME
);

SELECT u.UserID, u.UserName, o.OrderID, o.ProductName, o.OrderDate
FROM Users u
INNER JOIN Orders o ON u.UserID = o.UserID;

SELECT u.UserID, u.UserName, o.OrderID, o.ProductName, o.OrderDate
FROM Users u
LEFT JOIN Orders o ON u.UserID = o.UserID;

SELECT u.UserID, u.UserName, o.OrderID, o.ProductName, o.OrderDate
FROM Users u
RIGHT JOIN Orders o ON u.UserID = o.UserID;

SELECT u.UserID, u.UserName, o.OrderID, o.ProductName, o.OrderDate
FROM Users u
FULL JOIN Orders o ON u.UserID = o.UserID;

SELECT DISTINCT u.UserID, u.UserName, o.OrderID, o.ProductName, o.OrderDate
FROM Users u
INNER JOIN Orders o ON u.UserID = o.UserID;