小编rif*_*nan的帖子

我想只在derby数据库中检索十条记录.我一直在搜索教程:

select * from (select  ROW_NUMBER() OVER() AS rownum,name,effort from (select  name, effort from
(select TBL_PROJECT_DETAIL.P_NAME as Name, sum(TBL_TIMESHEET.EFFORT) as effort from
TBL_TIMESHEET join tbl_project_detail on TBL_TIMESHEET.PROJECT_ID = TBL_PROJECT_DETAIL.ID group by TBL_PROJECT_DETAIL.P_NAME) as New)
as new2)
as new3 
where rownum <= 10

我可以通过使用最后的位置将数据限制为10 rownum <= 10 ,但问题是数据不是order by先使用子句排序,所以我得到了10个随机数据.

当我把order by数据放在前面时给出rownum:

select * from (select  ROW_NUMBER() OVER() AS rownum,name,effort from 
(select  name, effort from
(select TBL_PROJECT_DETAIL.P_NAME as Name, sum(TBL_TIMESHEET.EFFORT) as effort from
TBL_TIMESHEET join tbl_project_detail …

这是示例查询:

payment_Type    payment_value       cost_type      cost value
Cost I          100                 Registration       40
Cost I          100                 books              40
Cost I          100                 Lab                40

该COST我有3个要素Cost_Type是有自己的Cost_value.

我想像这样操纵:

payment_Type    payment_value       cost_type      cost value     Payment_by_cost_type
Cost I          100                 Registration       40              40
Cost I          100                 books              40              40
Cost I          100                 Lab                40              20

关键是我想把它分成payment_value每一个cost_value.在该示例中,payment_by_cost变为40,40,20 = 100.

实验室cost_value是40但它可以分配值为20,因为仍然是上面划分的2成本类型.

我可以使用Payment_by_cost_type下一行记录中的值吗？我一直在尝试将值插入Payment_by_cost_type临时表,但select不能有insert语句.

有没有人对如何解决这个问题有任何想法？我一直在咨询DWH,他说必须使用Store程序才能通过查询完成.

我正在尝试使用POI从excel读取数据.如何检查这是否为空单元格？

我不知道遗失了什么我认为这应该是有效的:

java.util.Iterator<Row> rows = worksheet.rowIterator();

HSSFRow row = (HSSFRow) rows.next();
HSSFCell cellF1 = (HSSFCell) row.getCell(5);
if(cellF1.getCellType() == HSSFCell.CELL_TYPE_BLANK) {
  String val = "";
}

我在if语句(空指针)中出错,但只有当我使用它时我才能检查:

   while (rows.hasNext()) {
    HSSFRow row = (HSSFRow) rows.next();
    java.util.Iterator<Cell> cells = row.cellIterator();
    while (cells.hasNext()) {
      HSSFCell cell = (HSSFCell) cells.next();
      if(cell.getCellType() == HSSFCell.CELL_TYPE_BLANK) {
        String emptytype = "";
        System.out.println("empty");
      }
    }
  }