Question

我有两个表dbo.Supplier和dbo.L_ProductSupplier（AS LPST）以及LPST表上的所有产品ID，我想连接来自dbo.Supplier（AS ST）的供应商名称，该名称由SupplierID链接到LPST字段（每个产品可以有多个供应商）

e.g。查询应该采用这个：

LPST.ProductID  LPST.SupplierID ST.SupplierName
1                          A    CompanyA
1                          B    CompanyB
1                          C    CompanyC
2                          X    CompanyX
2                          Y    CompanyY
2                          Z    CompanyZ

并输出：

LPST.ProductID  SupplierName(s)
1               CompanyA / CompanyB /CompanyC
2               CompanyX / CompanyY / CompanyZ

我尝试过以下代码：

SELECT DISTINCT
LPST.ProductId,
STUFF((SELECT ',' + ST.SupplierName
FROM dbo.Supplier AS ST
WHERE LPST.SupplierId=ST.SupplierId
FOR XML PATH('')),1,1,'') AS SupplierNames 
FROM dbo.L_ProductSupplier AS LPST
GROUP BY LPST.ProductId

...但是它给出了错误：列'dbo.L_ProductSupplier.SupplierId'在选择列表中无效，因为它不包含在聚合函数或GROUP BY子句中。关于如何解决这个问题的任何想法？如果我删除“分组依据”，则它会报告LPST上的每一行而不连接。

还有另一种方法吗？我听说游标是一个选项，但我是SQL的新手，并不熟悉它们;在这种情况下，有没有人有游标经验？

Answer 1

怎么样

DECLARE @Supplier TABLE(
    SupplierId INT,
    SupplierName VARCHAR(50)
)

INSERT INTO @Supplier SELECT 1, 'A'
INSERT INTO @Supplier SELECT 2, 'B'

DECLARE @L_ProductSupplier TABLE(
    ProductId INT,
    SupplierId INT
)       

INSERT INTO @L_ProductSupplier SELECT 1, 1
INSERT INTO @L_ProductSupplier SELECT 1, 2


;WITH Vals AS (
        SELECT  LPST.ProductId,
                LPST.SupplierId,
                ST.SupplierName
        FROM    @L_ProductSupplier LPST LEFT JOIN
                @Supplier ST ON LPST.SupplierId = st.SupplierId
)
SELECT  LPST.ProductId,
        STUFF(
                (
                    SELECT ',' + ST.SupplierName
                    FROM Vals AS ST
                    WHERE LPST.ProductId=ST.ProductId
                    FOR XML PATH('')
                ),
                1,
                1,
                ''
            ) AS SupplierNames 
FROM    Vals AS LPST
GROUP BY    LPST.ProductId

SQL Fiddle DEMO

Answer 2

Declare @t table (ProductID int,  SupplierID varchar(1),SupplierName varchar(50))
insert into @t
select 1 ,                         'A'  ,  'CompanyA' union all
select 1                          , 'B'   , 'CompanyB' union all
select 1                         , 'C'   , 'CompanyC' union all
select 2                         , 'X'   , 'CompanyX' union all
select 2                         , 'Y'   , 'CompanyY' union all
select 2                         , 'Z'   , 'CompanyZ'

select distinct b.ProductID,stuff((select '/'+a.SupplierName from @t a where a.ProductID=b.ProductID FOR XML path('')),1,1,'')
from @t b

在MS SQL Server中进行组连接

2 个答案:

SQL Fiddle DEMO