如何从访问表中选择700条随机记录？

Question

这段代码给了我最后的700条记录，而不是700条随机记录。

private string strsqlcommandBeta = " select top 700 LEFT(patronvalue17, INSTR(30, patronvalue17, ' ') -1) as patronvalue1, Rnd([objectid]) AS Ran from objectaer " + 
" order by objectdate desc" + 
" "; 

Answer 1

我不是附近的MS Access，但是这给了一枪：

SELECT * FROM (
    SELECT top 700 LEFT(patronvalue17, INSTR(30, patronvalue17, ' ') -1) as patronvalue1, objectdate 
    FROM objectaer 
    ORDER BY Rnd([objectid])() 
) order by objectdate desc 

中RND（[OBJECTID]）应该给你一个随机数，通过什么样的排序，那么你你想在那之后。

Answer 2

SELECT * FROM (
    SELECT top 700 LEFT(patronvalue17, INSTR(30, patronvalue17, ' ') -1) as patronvalue1, objectdate 
    FROM objectaer 
    ORDER BY newid() 
) order by objectdate desc 

的newid()函数生成其可以为了排序的表中使用，得到在每次运行时不同结果的随机GUID。我不知道你是否真的需要外部选择，它是用来按日期排序随机项目的降序