动态枢轴 sql

Question

我正在尝试 select 来自客户 table、合同支出 table 和合同名称 table 的数据。我的 table 看起来像这样

Customers
CustomerID  CustomerName  Address          etc
1           "ABC Corp"   "123 Here Ave"
2           "Acme Corp"  "101 Lets Ave"

ContractTypes
ContractTypeID ContractName
1              "Website Hosting"
2              "Domain Hosting"
3              "Email Hosting"

ServiceSpend
ServiceSpendID  ContractTypeID  CustomerID  Spend
1               2               1           5.99
2               1               1           5.99
3               1               2           9.99

我想制作以下内容table

CustomerID CustomerName Address         DomainHosting WebsiteHosting
1          "ABC Corp"   "123 Here Ave"  9.99          5.99

目前我有以下有效的 sql 语句，但我需要能够动态定义列，因为我们需要能够向数据库添加额外的合同名称并仍然报告客户支出

select *
from 
(
SELECT        
Customers.CustomerID, Customers.ContactName, Customers.Address,                              ContractTypes.ContractName AS ContractName, ServiceSpend.Spend
FROM            
Customers INNER JOIN
ServiceSpend ON Customers.CustomerID = ServiceSpend.CustomerID 
INNER JOIN
ContractTypes ON ServiceSpend.ContractTypeID = ContractTypes.ContractTypeID
) src
pivot
(
sum(spend)
    for ContractName in ([Website Hosting],[Domain Hosting])) piv;

有谁知道我可以如何动态添加我的列

Answer 1

您必须使用动态 sql 为您的输出构建列：

DECLARE @Columns VARCHAR(1000) = STUFF((
    SELECT ',[' + ContactName + ']'
    FROM ContactTypes
    FOR XML PATH('')
    ),1,1,'')
DECLARE @Sql VARCHAR(1000) = '
    SELECT *
    FROM (
        SELECT        
            Customers.CustomerID,
            Customers.ContactName,
            Customers.Address,
            ContractTypes.ContractName,
            ServiceSpend.Spend
        FROM Customers
            INNER JOIN ServiceSpend
                ON Customers.CustomerID = ServiceSpend.CustomerID 
            INNER JOIN ContractTypes
                ON ServiceSpend.ContractTypeID = ContractTypes.ContractTypeID
        ) SRC
        PIVOT (SUM(Spend) FOR ContractName IN (' + @Columns + ')) piv;'
EXEC (@Sql)

动态枢轴 sql

dynamic pivot sql

sql

database

sql-server

pivot