我有三个表：tblProduct，lkpFoodgroup，tblCustomer。和一个联结表：jctCustomerFoodgroup
列是这样的：
**tblProduct**
+---+----------------+
|PK |int_ProductID |
|FK |int_FoodgroupID |
| |str_ProductName |
+---+----------------+
**lkpFoodgroup**
+---+-------------------+
|PK |int_FoodgroupID |
| |str_FoodgroupHandle|
+---+-------------------+
**tblCustomer**
+---+----------------+
|PK |int_CustomerID |
| |str_CustomerName|
+---+----------------+
**jctCustomerFoodgroup**
+---+----------------+
|PK |int_CustomerID |
|PK |int_FoodgroupID |
| |int_ProductID |
+---+----------------+
这些表中最简单的是查找：
**lkpFoodgroup**
+---------------+-------------------+
|int_FoodgroupID|str_FoodgroupHandle|
+---------------+-------------------+
|1 |fruit |
|2 |meat |
|3 |bread |
|4 |cheese |
+---------------+-------------------+
接下来是客户：
**tblCustomer**
+----------------+-------------------+
|int_CustomerID |str_CustomerName |
+----------------+-------------------+
|1 |Bob |
|2 |Sally |
|3 |Jane |
|4 |Billy |
+----------------+-------------------+
tblProduct上可能有许多产品具有相同的Foodgroup。还有一些产品Foodgroups没有产品：
**tblProduct**
+---------------+-----------------+----------------+
|int_ProductID |int_FoodgroupID |str_ProductName |
+---------------+-----------------+----------------+
|1 |1 |apple |
|2 |1 |banana |
|3 |1 |orange |
|4 |1 |pear |
|5 |2 |chicken |
|6 |2 |beef |
|7 |2 |fish |
|8 |2 |turkey |
|9 |3 |white |
|10 |3 |wheat |
+---------------+-----------------+----------------+
联结表上的PK是一个组合的int_CustomerID和int_FoodgroupID - 这意味着任何客户只能为每个Foodgroup选择一个产品：
**jctCustomerFoodgroup**
+---------------+-----------------+--------------+------------------------+
|int_CustomerID |int_FoodgroupID |int_ProductID | --meaning |
+---------------+-----------------+--------------+------------------------|
|1 | 1 |1 | --Bob, fruit, apple |
|1 | 2 |6 | --Bob, meat, beef |
|1 | 3 |9 | --Bob, bread, white |
|2 | 1 |3 | --Sally, fruit, orange |
|2 | 2 |5 | --Sally, meat, chicken |
|3 | 1 |3 | --Jane, fruit, orange |
|3 | 3 |9 | --Jane, bread, white |
|3 | 2 |6 | --Jane, meat, beef |
+---------------+-----------------+--------------+------------------------+
我正在寻找一个可以给我这样结果的查询：
**spGetCustomerProductSelections(1) --Get Bob's choices**
+----------------+---------------+-------------------+-------------+---------------+
|int_CustomerID |int_FoodgroupID|str_FoodgroupHandle|int_ProductID|str_ProductName|
+----------------+---------------+-------------------+-------------+---------------+
|1 |1 |fruit |1 |apple |
|1 |2 |meat |6 |beef |
|1 |3 |bread |9 |white |
|1 |4 |cheese |null |null |
+----------------+---------------+-------------------+-------------+---------------+
**spGetCustomerProductSelections(2) --Get Sally's choices**
+----------------+---------------+-------------------+-------------+---------------+
|int_CustomerID |int_FoodgroupID|str_FoodgroupHandle|int_ProductID|str_ProductName|
+----------------+---------------+-------------------+-------------+---------------+
|2 |1 |fruit |3 |orange |
|2 |2 |meat |5 |chicken |
|2 |3 |bread |null |null |
|2 |4 |cheese |null |null |
+----------------+---------------+-------------------+-------------+---------------+
**spGetCustomerProductSelections(4) --Get Billy's choices**
+----------------+---------------+-------------------+-------------+---------------+
|int_CustomerID |int_FoodgroupID|str_FoodgroupHandle|int_ProductID|str_ProductName|
+----------------+---------------+-------------------+-------------+---------------+
|4 |1 |fruit |null |null |
|4 |2 |meat |null |null |
|4 |3 |bread |null |null |
|4 |4 |cheese |null |null |
+----------------+---------------+-------------------+-------------+---------------+
任何帮助？
答案 0 :(得分：0)
您应该使用外连接（左，右或全）。这些连接将包含空值。
答案 1 :(得分：0)
请不要将您的程序命名为以“sp”开头。它将开始在master数据库中搜索，之后才会回到你的数据库。
您的架构和数据的DDL
create table lkpFoodgroup
(int_FoodgroupID int, str_FoodgroupHandle varchar(max))
insert lkpFoodgroup values
(1,'fruit'),
(2,'meat'),
(3,'bread'),
(4,'cheese');
create table tblCustomer
(int_CustomerID int, str_CustomerName varchar(max))
insert tblCustomer values
(1,'Bob'),
(2,'Sally'),
(3,'Jane'),
(4,'Billy');
create table tblProduct
(int_ProductID int, int_FoodgroupID int, str_ProductName varchar(max))
insert tblProduct values
(1,'1','apple'),
(2,'1','banana'),
(3,'1','orange'),
(4,'1','pear'),
(5,'2','chicken'),
(6,'2','beef'),
(7,'2','fish'),
(8,'2','turkey'),
(9,'3','white'),
(10,'3','wheat');
create table jctCustomerFoodgroup
(int_CustomerID int, int_FoodgroupID int, int_ProductID varchar(max))
insert jctCustomerFoodgroup values
(1,'1','1'),
(1,'2','6'),
(1,'3','9'),
(2,'1','3'),
(2,'2','5'),
(3,'1','3'),
(3,'3','9'),
(3,'2','6');
存储过程代码
create proc uspGetCustomerProductSelections @customerID int as
select c.int_CustomerID, l.int_FoodgroupID, l.str_FoodgroupHandle, j.int_ProductID, p.str_ProductName
from tblCustomer c
cross join lkpFoodgroup l
left join jctCustomerFoodgroup j on j.int_CustomerID = c.int_CustomerID and j.int_FoodgroupID = l.int_FoodgroupID
left join tblProduct p on p.int_ProductID = j.int_ProductID
where c.int_CustomerID = @customerID
示例执行
exec uspGetCustomerProductSelections 1
输出
int_CustomerID int_FoodgroupID str_FoodgroupHandle int_ProductID str_ProductName
-------------- --------------- ---------------------------------------------------
1 1 fruit 1 apple
1 2 meat 6 beef
1 3 bread 9 white
1 4 cheese NULL NULL