带有计数和总和的 TSQL 交叉应用答案

【问题标题】：TSQL Cross Apply with Count and Sum带有计数和总和的 TSQL 交叉应用
【发布时间】：2015-03-05 20:51:08
【问题描述】：

我刚刚发现了 CROSS APPLY 运算符，并认为它在操作派生列进行计算方面非常有用。

所以，我尝试了以下方法：

SELECT leadYear,TotalLeadsCalled,SuccessLeadsCalled,SuccessLeadsPercent
FROM dbo.tblBinOutboundCallActivity 
CROSS APPLY(VALUES (YEAR(leadactivitydate))) AS a1(leadyear) 
CROSS APPLY(VALUES (COUNT(leadStatusID))) AS a2(TotalLeadsCalled) 
CROSS APPLY(VALUES (COUNT(CASE WHEN leadStatusID = 2 THEN 1 ELSE NULL END))) AS a3(SuccessLeadsCalled) 
CROSS APPLY(VALUES (SUM((SuccessLeadsCalled/TotalLeadsCalled)*100))) AS a4(SuccessLeadsPercent) 
GROUP BY leadYear

但我收到以下错误：

APPLY 右侧的聚合不能引用来自左边。

我不太明白这个错误，尤其是第一个交叉应用实际上是孤立地工作的。我是不是完全搞错了这个概念？

【问题讨论】：

标签： tsql cross-apply

【解决方案1】：

交叉应用适用于行级别。

“对于左边的每一行，我们在右边应用一个函数”。

您的聚合对每行没有意义。

【讨论】：

【解决方案2】：

这些都行。

仅使用应用：

SELECT leadYear,TotalLeadsCalled,SuccessLeadsCalled,SuccessLeadsPercent
FROM dbo.tblBinOutboundCallActivity a
    CROSS APPLY (SELECT YEAR(leadactivitydate) leadyear FROM dbo.tblBinOutboundCallActivity WHERE YEAR(leadactivitydate) = YEAR(a.leadactivitydate)) a1
    CROSS APPLY (SELECT COUNT(leadStatusID) TotalLeadsCalled FROM dbo.tblBinOutboundCallActivity WHERE YEAR(leadactivitydate) = a1.leadyear) a2
    CROSS APPLY (SELECT COUNT(CASE WHEN leadStatusID = 2 THEN 1 ELSE NULL END) SuccessLeadsCalled FROM dbo.tblBinOutboundCallActivity WHERE YEAR(leadactivitydate) = a1.leadyear) a3
    CROSS APPLY (SELECT 100.*SuccessLeadsCalled/TotalLeadsCalled SuccessLeadsPercent) a4
GROUP BY leadYear,TotalLeadsCalled,SuccessLeadsCalled,SuccessLeadsPercent

CTE 和应用：

WITH Years AS
(
    SELECT YEAR(leadactivitydate) leadyear
    FROM dbo.tblBinOutboundCallActivity
    GROUP BY YEAR(leadactivitydate)
)
    SELECT leadYear,TotalLeadsCalled,SuccessLeadsCalled,SuccessLeadsPercent
    FROM Years      
        CROSS APPLY (SELECT COUNT(leadStatusID) TotalLeadsCalled FROM dbo.tblBinOutboundCallActivity WHERE YEAR(leadactivitydate) = leadyear) a2
        CROSS APPLY (SELECT COUNT(CASE WHEN leadStatusID = 2 THEN 1 ELSE NULL END) SuccessLeadsCalled FROM dbo.tblBinOutboundCallActivity WHERE YEAR(leadactivitydate) = leadyear) a3
        CROSS APPLY (SELECT 100.*SuccessLeadsCalled/TotalLeadsCalled SuccessLeadsPercent) a4

【讨论】：