MySql 语法错误（使用连接）

Question

我在MYSQL语法中找不到错误：

"SELECT customer.CustomerCode, customer.CustomerName, customer.CustomerAddress, customer.CustomerHandphone, customer,CustomerEmail, product.ProductCode, product.ProductName, product.ProductPrice, orderdetail.OrderCode, orderdetail.ProductCode, orderdetail.ProductPrice, orderlist.OrderCode, orderlist.CustomerCode, orderlist.OrderPrice " +
                     "FROM customer INNER JOIN (product INNER JOIN (orderlist INNER JOIN(orderdetail INNER JOIN ON orderlist.OrderCode = orderdetail.OrderCode) ON product.ProductCode = orderdetail.ProductCode) ON customer.CustomerCode = orderlist.CustomerCode) " +
                     "Where orderlist.OrderCode [email protected] " +
                        "GROUP BY customer.CustomerCode, customer.CustomerName, customer.CustomerAddress, customer.CustomerHandphone, customer,CustomerEmail, product.ProductCode, product.ProductName, product.ProductPrice, orderdetail.OrderCode, orderdetail.ProductCode, orderdetail.ProductPrice, orderlist.OrderCode, orderlist.CustomerCode, orderlist.OrderPrice";"

错误如下 1064 - 您的 SQL 语法有错误；检查与您的 MariaDB 服务器版本相对应的手册，了解在第 1 行 'ON orderlist.OrderCode = orderdetail.OrderCode) ON Product.ProductCode = orderde' 附近使用的正确语法

Answer 1

使用每个

ON

后面的

JOIN

子句编写查询。 这更容易阅读和编写，并且可能是您的问题：

SELECT c.CustomerCode, c.CustomerName, c.CustomerAddress, c.CustomerHandphone, c.CustomerEmail,
       p.ProductCode, p.ProductName, p.ProductPrice,
       od.OrderCode, od.ProductCode, od.ProductPrice, od.OrderCode,
       ol.CustomerCode, ol.OrderPrice " +
FROM orderlist ol INNER JOIN
     orderdetail od
     ON ol.orderCode = od.OrderCode INNER JOIN
     customer c 
     ON c.CustomerCode = ol.CustomerCode INNER JOIN
     product p
     ON p.ProductCode = od.ProductCode;

此外，

ORDER BY

似乎没有必要。 通常它会与聚合函数一起使用。 如果您以某种方式获得重复项（这似乎不太可能），请使用

SELECT DISTINCT

。

最后，我不明白这个：

Where ol.OrderCode = @orderdetail.OrderCode

我认为

@orderdetail.OrderCode

不是有效的语法。 如果你想传入一个变量，它看起来更像是：

Where ol.OrderCode = @OrderCode

Answer 2

此 SQL 语法错误是由于

ON

子句放置不当造成的。下面是编写 SQL 查询的更好方法：

SELECT enter code here
    customer.CustomerCode, 
    customer.CustomerName, 
    customer.CustomerAddress, 
    customer.CustomerHandphone, 
    customer.CustomerEmail, 
    product.ProductCode, 
    product.ProductName, 
    product.ProductPrice, 
    orderdetail.OrderCode, 
    orderdetail.ProductCode, 
    orderdetail.ProductPrice, 
    orderlist.OrderCode, 
    orderlist.CustomerCode, 
    orderlist.OrderPrice
FROM 
    customer
    INNER JOIN orderlist ON customer.CustomerCode = orderlist.CustomerCode
    INNER JOIN orderdetail ON orderlist.OrderCode = orderdetail.OrderCode
    INNER JOIN product ON orderdetail.ProductCode = product.ProductCode
WHERE 
    orderlist.OrderCode = @orderdetail.OrderCode
GROUP BY 
    customer.CustomerCode, 
    customer.CustomerName, 
    customer.CustomerAddress, 
    customer.CustomerHandphone, 
    customer.CustomerEmail, 
    product.ProductCode, 
    product.ProductName, 
    product.ProductPrice, 
    orderdetail.OrderCode, 
    orderdetail.ProductCode, 
    orderdetail.ProductPrice, 
    orderlist.OrderCode, 
    orderlist.CustomerCode, 
    orderlist.OrderPrice;