随着数据库的发展,如今的数据库可以储存大量的数据,内存也是越来越大,但是无论您的内存多大,内存总是显得不够用,这时就要涉及到分页,下文中将为大家带来详细的数据库分页操作。
1.oracle:
select * from ( select row_.*, rownum rownum_ from ( query_sql ) row_ where rownum == min
2.sql server:
select top @pagesize * from tablename where id not in (select top @pagesize*(@page-1) id from tablename order by id) order by id
3.mysql
select * from tablename limit position, counter
4.db2
select * from (select *,rownumber() as row_next from tablename) where row_next between min and max
分页方案一:(利用not in和select top分页)效率次之 语句形式:
select top 10 * from testtable where(id not in (select top 20 id from testtable orderby id)) orderbyid select top 页大小 * from testtable where( id not in (select top 每页大小-1*待查询页数-1 id from 表 orderby id)) orderbyid
思路:先查询出待查询页之前的全部条数的id,查询id不在这些id中的指定数量条数。
分页方案二:(利用id大于多少和select top分页)效率最高 语句形式:
select top 10 * from testtable where(id>(select max(id) from(select top20 id from testtable orderbyid)as t))orderby id select top 页大小* from testtable where(id>(select max(id) from(select top 每页大小*待查询页数-1 id from 表 orderby id)as t)) orderby id
思路:先获得待查询页的之前全部条数id,获得它们当中最大的id号,以此最大id号为标志,查找比这个id号大的指定条数。
分页方案三:select top pagesize * from(select top npage*pagesize * from yourtable order by id) as a order by id desc select top 每页条数 * from(select top 待查询页*每页条数) * from yourtable order by id)as a order by id desc
思路:先正排序查询出待查询页之前(包括当前页)的全部条数,然后将其倒排序,取指定条数。