INNER JOIN 操作符
INNER JOIN 关键字在表中存在至少一个匹配时返回行。
SQL INNER JOIN 语法
SELECT column_name(s)
FROM table1
INNER JOIN table2
ON table1.column_name=table2.column_name;
或：
SELECT column_name(s)
FROM table1
JOIN table2
ON table1.column_name=table2.column_name;
注释：INNER JOIN 与 JOIN 是相同的 (交集)。
Demo
SELECT Customers.CustomerName, Orders.OrderID
FROM Customers
INNER JOIN Orders
ON Customers.CustomerID=Orders.CustomerID
ORDER BY Customers.CustomerName;
Mysql
也可以用上面的写法，等同下面
SELECT Customers.CustomerName, Orders.OrderID
FROM Customers , Orders
WHERE Customers.CustomerID=Orders.CustomerID
ORDER BY Customers.CustomerName;