xy294636185的博客

ACM模式输出模板： import java.util.Scanner; public class Main{ public static void main(String[] args){ Scanner sc = new Scanner(System.in); int n = sc.nextInt(); } } 输入浮点：float n = sc.nextFloat(); 取整： 1.Math.round(n) 2.ans-(int)ans>=0.5?(int)(ans+1):(int

POI读取文件： 1.读取EXCEL文件空指针异常： 解决： int target_qty = 0; //添加Row.MissingCellPolicy.CREATE_NULL_AS_BLANK参数即可解决空指针异常 if(row.getCell(i+3,Row.MissingCellPolicy.CREATE_NULL_AS_BLANK).getCellType().equals(CellType.BLANK)) { target_qty = 0; }else{ target_

select a.factory,b.product,a.area,if(b.total is null,0,b.total) as total from tb_area a left join ( select factory,product,area,count(*) as total from a where DATE_FORMAT(newDate,'%Y-%m-%d') = '2020-03-26' GROUP BY factory,product,area ) b on a.area = b.ar