Question

这里我有五张桌子的数据。

表1 users有三列：

uid, username, data

表2 users_order有三列：

uid, orders_id, users_email

表3 order_products有三列：

orders_id, product_id, product_name

表4用户配置文件值有三列（下面是行中的数据）

uid, fid, values
1     1   firstname
1     2   lastname

因此，通过表1 - 3，我能够像这样编写查询

SELECT users.uid AS uid, users.username AS username, 
       users_order.orders_id AS orderId,     
       users_order.users_email AS userEmail, 
       order_products.product_name AS  productName 
WHERE users_order.uid = users.uid
AND users_order.orders_id = order_products.orders_id
AND order_products.product_id = 5 ;

以上查询将给出

的结果

uid   usersname   orderId   usersEmail       productName 
1    xxusername   123       xxxuser@gmail    Product 1

我想将表4数据Firstname和Last Name引入查询结果。所以，最终的查询将是

uid    username    orderId     usersEmail    productName    FirstName    LastName

需要有关添加表4数据的查询的帮助。

Answer 1

试试这个：

SELECT 
  u.uid AS uid, 
  u.username AS username, 
  o.orders_id AS orderId,     
  o.users_email AS userEmail, 
  p.product_name AS  productName,
  MAX(CASE WHEN f.fid = 1 THEN `values` END) AS 'First Name',
  MAX(CASE WHEN f.fid = 2 THEN `values` END) AS 'Last Name'
FROM users u 
INNER JOIN users_order o ON o.uid = u.uid
INNER JOIN order_products p ON o.orders_id = o.orders_id
INNER JOIN usersprofile f ON u.uid = f.uid
WHERE p.product_id = 5 
GROUP BY u.uid, u.username, o.orders_id, o.users_email, p.product_name;

SQL Fiddle Demo

这会给你：

| UID |   USERNAME | ORDERID |     USEREMAIL | PRODUCTNAME | FIRST NAME | LAST NAME |
-------------------------------------------------------------------------------------
|   1 | xxusername |     123 | xxxuser@gmail |   product 1 |        sam |       lin |

假设用户个人资料表中的每个values条目都有两个fid值1,2，表示firstname和lastname。

将MySql表与字段内的查询值连接起来

1 个答案:

SQL Fiddle Demo