大数据下的分页语句
pageSize:一页几条数据
pageNumber:当前页
mysql:
select * from students order by id limit " + pageSize*(pageNumber-1)+ "," + pageSize;
oracle:
select * from (select *,rownum rid from (select * fromstudents order by postime desc) where rid<=" + pagesize*pagenumber +") as t where t>" +pageSize*(pageNumber-1);
在业务中处理分页:
// 定义的总记录数 int dataCount = 0; // 定义当前页 // pageNum = 1; // 定义总页数 int pageCount = 0; // 定义每页显示条数 int pageSize = 30; // 开始索引 int startIndex = 0; //统计总记录数 dataCount=photoService.countPhoto(); //计算共多少页 if(dataCount%pageSize == 0){ pageCount = dataCount/pageSize; }else { pageCount = dataCount/pageSize + 1; } if(pageNum!=0){ startIndex = (pageNum-1)*pageSize; }
SQL语句:select * from emp limit startIndex,30