sql-server - SQL - SUM-CASE-除以零错误

Question

我想保护以下语句免受被零除错误的影响。我怎样才能做到这一点？

SELECT [MyColumn] = sum( 
   case when v.Process_FundingDt 
   between @begDt and @endDt  
   and v.Loan_Purpose_Desc = 'PURCHASE' 
   then v.Loan_LoanAmt 
   else 0 
   end
 ) / sum (
   case when v.Process_FundingDt 
   between @begDt and @endDt 
   then v.Loan_LoanAmt else 0 
   end
 )

Answer 1

这可能会有所帮助：

select [MyColumn] = case when Denominator = 0 then NULL else Numerator / Denominator end
  from (
   select sum( 
   case when v.Process_FundingDt between @begDt and @endDt and v.Loan_Purpose_Desc = 'PURCHASE' then v.Loan_LoanAmt 
     else 0 end ) as Numerator,
   sum (
   case when v.Process_FundingDt between @begDt and @endDt then v.Loan_LoanAmt
     else 0 end ) as Denominator
   ) as Edgar

添加缺少的FROM子句可能会更好。

当然，它可能会与此功能发生冲突，具体取决于查询优化器的功能。

Answer 2

您可以使用此处提到的NULLIF方法：如何避免除以零错误

SELECT [MyColumn] = sum( 
   case when v.Process_FundingDt 
   between @begDt and @endDt  
   and v.Loan_Purpose_Desc = 'PURCHASE' 
   then v.Loan_LoanAmt 
   else 0 
   end
 ) / NULLIF(sum (
   case when v.Process_FundingDt 
   between @begDt and @endDt 
   then v.Loan_LoanAmt else 0 
   end, 0)
 )