如何在sql中實現excel sumif類型函數？

Question

如何根據另一列中的特定標準集在列中添加不同的值？ 同，可以在Excel中使用SUMIF

Answer 1

綜上所述一列的所有值符合特定條件的行來完成：

SELECT Sum(value1) FROM Table WHERE value2=something 

Answer 2

Select SalesAgent 
     ,JanSales = sum(case when SalesMonth=1 then Sales else 0 end) 
     ,FebSales = sum(case when SalesMonth=2 then Sales else 0 end) 
     ... {march - november} 
     ,DecSales = sum(case when SalesMonth=12 then Sales else 0 end) 
     ,Total = sum(Sales) 
From SalesData 
Group By SalesAgent 
Order By SalesAgent