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。
AD:
1.Oracle:
- select * from ( select row_.*, rownum rownum_ from ( query_SQL ) row_ where rownum =< max) 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
1.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
2.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
3.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
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