如何选择50％的最后一行数据库表

问题描述

如何选择最后一行的50％数据库表..
就像我有100条记录.我想获得最后50％的记录.我该如何获得????


请帮助


Thanx

HOW TO SELECT 50% LAST ROW FRO DATABASE TABLE..
like i hv 100 records.i want to get last 50% record .how do i get????


plz help


Thanx

推荐答案

Select TOP 50 PERCENT * from table_name ORDER BY COLUMN_NAME DESC

SELECT     TOP   (SELECT     COUNT(*) / 2 AS Expr1
  FROM          QuestionTab) qid, qname, opt1, opt2, opt3, opt4, ans
FROM         QuestionTab AS QuestionTab_1
order by qid desc

但是这里选择上半条记录

您可以按id
的顺序获取最后一半
希望你明白我说的

最好的

But here it selects top half record

you can get last half by order by id

I hope you got What I said

All the Best

SELECT * FROM tablename LIMIT 50, 50

即从第50条记录开始选择50条记录.

这将适用于MySQL，但是我们需要知道您的DBMS平台是什么，因为每个平台的工作方式都不同(例如，MSSQL没有LIMIT！)

对于MSSQL，请尝试:

i.e. select 50 records, starting at the 50th record.

This will work for MySQL but we need to know what your DBMS platform is as each platform works differently (e.g. MSSQL doesn''t have LIMIT!)

For MSSQL try:

SELECT TOP 50 PERCENT * from tablename ORDER BY id desc

如果"id"是自动递增的主键字段，则此方法有效.

This works if ''id'' is a primary key field which auto increments.

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