Question

我之前创建了一个查询，用于连接与客户关联的员工。每个客户只分配了2个客户。我的问题是在执行查询之后，对于每个客户，它将所有员工与每个客户相关联，而不是2.这是我到目前为止所拥有的：

SELECT C.customer_id, 
       C.l_name                         AS Surname, 
       C.f_name                         AS 'First Name', 
       C.travel_date, 
       T.tour_name, 
       Group_concat(S.f_name, S.l_name) AS Staff_Concat 
FROM   customers AS C 
       LEFT JOIN tour AS T 
              ON C.tour_id = T.tour_id 
       LEFT JOIN staff_day AS SD 
              ON C.tour_id = SD.tour_id 
       LEFT JOIN staff_day AS SD_2 
              ON SD_2.sd_date = C.travel_date 
       LEFT JOIN staff AS S 
              ON SD.staff_id = S.staff_id 
WHERE  C.travel_date >= '2014-07-08 00:00:00' 
       AND C.travel_date <= '2014-07-08 23:59:59' 
       AND C.customer_id NOT IN (SELECT O.customer_id 
                                 FROM   customers AS C, 
                                        orders AS O 
                                 WHERE  C.travel_date >= '2014-07-08 00:00:00' 
                                        AND C.travel_date <= 
                                            '2014-07-08 23:59:59' 
                                        AND C.customer_id = O.customer_id) 
GROUP  BY C.customer_id

我尝试过使用：

SD.staff_ID = S.staff_ID

在where子句中但没有太多运气。我觉得好像：

LEFT JOIN Staff AS S ON SD.staff_ID = S.staff_ID

是不必要的，但我似乎无法解释原因。这是我得到的结果：

6166    customer_Name   2014-07-08 Wildthing    Staff1, Staff2, staff3...staff10

我的预期结果应该是：

6166    customer_Name   2014-07-08 Wildthing    Staff1, staff2

如果这是重复，请再次道歉。我做了一些研究，但现在我已经走到了尽头。

以下是数据库架构：

Table structure for table Customers
Column  Type    Null    Default
customer_ID int(11) No  
f_Name  varchar(30) Yes NULL
l_Name  varchar(30) No  
address varchar(100)    No  
suburb  varchar(30) No  
state   varchar(30) No  
country varchar(30) No  
postcode    varchar(30) No  
email   varchar(50) No  
phone   varchar(20) No  
child_1 varchar(30) Yes NULL
child_2 varchar(30) Yes NULL
child_3 varchar(30) Yes NULL
child_4 varchar(30) Yes NULL
travel_Date datetime    No  
signature   text    No  
terms   tinyint(1)  No  
interested_video    tinyint(1)  Yes 0
specials    tinyint(1)  Yes NULL
tour_ID int(11) Yes NULL
updated timestamp   No  CURRENT_TIMESTAMP

Table structure for table Staff
Column  Type    Null    Default
f_Name  varchar(30) No  
l_Name  varchar(30) No  
comm_Value  int(3)  No  
staff_Type  varchar(50) No  
staff_ID    int(11) No  
bus_ID  int(11) No  

Table structure for table Staff_Day
Column  Type    Null    Default
sd_ID   int(11) No  
staff_ID    int(4)  No  
tour_ID int(4)  No  
sd_Date datetime    No  

Table structure for table Tour
Column  Type    Null    Default
tour_Name   varchar(30) No  
tour_ID int(11) No  
bus_ID  int(11) No

LEFT JOIN（包括模式）后，SQL查询未返回预期结果

0 个答案: