postgres=#selectname, agefromemployee order by random() limit5; name|age---+---nam490|25nam444|32nam943|25nam143|35nam690|32(5rows)postgres=#selectname, agefromemployee order by0.1limit5; ERROR: non-integer constantinORDER BY LINE1:selectname, agefromemployee order by0.1limit5;^postgres...
简介: 标签PostgreSQL , 数组 , 随机 , order by random()背景在业务系统中,有些场景会用到随机返回的功能,例如论坛,有很多帖子(比如有100万贴),有些是精华帖(比如有5万贴),为了让精华帖可以均衡的被访问,需要将5万贴随机的分页返回给用户。标签 PostgreSQL , 数组 , 随机 , order by random() 背景 在...
postgres=#selectname, agefromemployee order by random() limit5; name|age---+---nam490|25nam444|32nam943|25nam143|35nam690|32(5rows)postgres=#selectname, agefromemployee order by0.1limit5; ERROR: non-integer constantinORDER BY LINE1:selectname, agefromemployee order by0.1limit5;^postgres...
您的ORDER BY逻辑应该总是足够具体,以便按照您想要的方式进行排序。因此,如果希望Kanna的记录首先出现在limit查询中,则应在名称上添加降序排序级别: SELECT * FROM friends ORDER BY age DESC, name DESC LIMIT 1; 即使Postgres的排序在某种顺序上看起来是稳定的,行为也可能随着底层数据的变化而改变。而且几乎可以肯...
App\User::inRandomOrder()->toSql(); Simply results in select * from `users` order by RAND() The decision regarding whether to use Laravel or not is not the main factor here. The choice of SQL engine database (MySQL or Postgres, for instance) is what matters. ...
分页功能是所有网页上都需要提供的功能,当要展示的条目比较多时,就需要进行分页,不但能减小数据库读取...
The following test gives random results: EditorResponse.objects.order_by('reader_letter__reader_name') The appended patch fixes this test by requesting a second level ordering.by Michael Radziej <mir@…>, 18年 ago Attachment: order.diff added ...
Generate random URL to download a file Generate Reference number for booking generate row number by descending order Generate Window.Open In vb.net Script Get location name from latitude and longitude Get Client Mac Address in Asp.Net Web Application Get Client pc name Get Column Names in DataSet...
index一定是连续的。...return false } func (this *RandomizedSet) getRandom() int { if this.size == 0 { return -1 27030 Django中的QuerySet 常用的QuerySetf方法 1> all(): 查询所有结果 filter(**kwargs): 它包含了与所给筛选条件相匹配的对象 ...get(**kwargs): 返回与所给筛选条件相...
postgres=#createtabletbl (idint, c1int, c2int, c3int, c4int);CREATETABLE 2、写入一批随机数据,ID从1到1000万。 postgres=#insertintotblselectgenerate_series(1,10000000), random()*100, random()*100, random()*100, random()*100;INSERT010000000 ...