随机提取10条记录的例子

SQL随机抽取N条记录的实现方法详解 在数据库开发与数据分析中,随机抽取N条记录是一项常见且关键的操作。它广泛应用于A/B测试、抽样调查、推荐系统、数据预览等场景。SQL提供了多种实现方式,不同数据库系统(如MySQL、PostgreSQL、SQL Server、Oracle、SQLite)均有其特定的函数与机制来支持随机排序与抽样。本章将介绍随机抽取记录的基本概念,包括其业务意义、技术实现的通用逻辑,并为后续章节按数据库系统展开详细实现与优化策略打下基础。 阅读详情

 随机提取10条记录的例子:
Sql server:

select top 10 * from 表 order by newid()

Access:

SELECT top 10 * FROM 表 ORDER BY Rnd(id)

Rnd(id) 其中的id是自动编号字段,可以利用其他任何数值来完成

比如用姓名字段(UserName)

SELECT top 10 * FROM 表 ORDER BY Rnd(len(UserName))

MySql:

Select * From 表 Order By rand() Limit 10 

 

SQL 随机抽取数据 SQL Server 对表随机抽取指定条数的数据 立即下载

相关推荐

四种数据库随机获取10条数据的方法

主要介绍了四种数据库随机获取10条数据的方法,需要的朋友可以参考下

SqlServer随机取条数

Select TOP 10 * From dbo.T_Course ORDER BY NEWID() 

Todd Li的博客 1793

如何从数据库中随机取出10条记录的方法

如何从数据库中随机取出10条记录的方法

SQL随机提取N条记录

随机提取10条记录的例子: Sql server: select top 10 * from 表 order by newid() Access: SELECT top 10 * FROM 表 ORDER BY Rnd(id) Rnd(id) 其中的id是自动编号字段,可以利用其他任何数值来完成 比如用姓名字段(UserName) SELECT top 10 * FROM 表 ORDER BY R

hzivan的专栏 1182

2.2.1.3-移动平均线(python画k线、均线、5日线、买卖点图、python均线策略)

* 绘制一个k线图,也就是蜡烛图 * 计算5日均线值、10日均线值 * 在k线图上,绘制5日线和10日线图 * 在5日线上,绘制与10日线的交叉点(上穿、下穿时) python画k线、均线、5日线、买卖点图、python均线策略

KelvinLiu 3413

导数与微分在 FPS 射击游戏中的实际应用:把“手感”算出来

摘要:射击游戏开发中,单线程适用于简单小游戏(如单机打靶),所有任务由主线程顺序处理,代码简单但效率较低;多线程则适合复杂场景(如多人在线3D大作),通过渲染、逻辑、网络、音效等线程分工协作,确保画面流畅、响应迅速和实时同步。选择依据取决于游戏复杂度、联网需求和性能要求,小型游戏用单线程,大型高要求项目必须采用多线程架构。(149字)

本博客聚焦游戏开发技巧、创业实战心得及大学热门课程干货。这里既有技术深度,也有思维广度,无论你是开发者、创业者还是高校学子,都能在这里找到适合自己的成长之路! 3278

sql 中随机函数 newid()

从A表随机取10条记录,用SELECT TOP 10 * FROM ywle order by newid() order by 一般是根据某一字段排序,newid()的返回值 是uniqueidentifier ,order by newid()随机选取记录是如何进行的 newid()在扫描每条记录的时候都生成一个值, 而生成的值是随机的, 没有大小写顺序. 所以最终结果再按这个排序, 排序的结...

weixin_30522095的博客 561

LeRobot 官方论文:一个用于端到端机器人学习的开源库

本文介绍了一个名为LeRobot的开源库,旨在解决机器人学习领域的碎片化问题。该库提供了端到端的技术栈,包括统一的机器人中间件API、标准化的数据集格式(LeRobotDataset)、优化的推理栈以及多种最先进机器人学习算法的实现。LeRobot支持多种低成本开源机器人平台(如SO-10X、ALOHA-2等),通过共享中间件实现便捷的遥操作和数据收集。其数据集格式已广泛应用于社区,截至2025年9月已有16,000多个数据集公开共享。该库还支持流式处理大规模数据,降低了研究门槛。在模型方面,LeRobot

2506_90492529的博客 906

SqlServer 找出随机的多少条数据

有时候可能是一些活动要抽出得奖人或选出抽查的一些名单,就常常会使用到 Order BY Newid() 的方式来做随机数选出,  Select TOP N * From TABLE Order By NewID()

Haibing的博客 3713

(一)深入理解Bluez协议栈之蓝牙Mesh的支持(1/5)

BlueZ是Linux官方蓝牙协议栈。它是一个基于GNU General Public License (GPL)发布的开源项目,从Linux 2.4.6开始便成为Linux 内核的一部分。如果你是linux平台开发蓝牙的的工程师,肯定会接触过Bluez协议栈,hciconfig,hciattach,hciconfig等工具都是很好用的工具。

3321

机器人外接 USB 音响完整配置指南

摘要:本文介绍了为机器人配置外接音响的方法。由于内置音响音量小且有散热噪音,建议使用Type-C接口外接音响。配置步骤包括:1)通过aplay -l命令查看音响端口信息;2)使用aplay命令测试音频播放;3)通过amixer命令设置音量。关键点在于正确识别音响的卡号(如card 2)和设备号(如device 0),并在命令中准确配置这些参数即可实现外接音响的正常使用。

m0_47999117的博客 356

从数据库获取 10 条随机数据

从数据库获取 10 条随机数据SQL Server:SELECT TOP 10 * FROM T_USER ORDER BY NEWID();Oracle:SELECT * FROM (SELECT * FROM T_USER ORDER BY DBMS_RANDOM.RANDOM()) WHERE RONUM <= 10;MySQL:从 MySQL 随机选取数据最简单的办法就是使用 ”ORDER

独一无二的小个性 1万+

图神经网络实战——总结 | 图神经网络展望

短短数年时间,图神经网络 (Graph Neural Networks, GNN) 已经成为一种重要的深度学习架构,并且已经广泛应用于各个行业。通过本专栏的学习,能够对图学习和 GNN 领域有一个全面的了解,并能为各种应用设计、构建GNN模型。

盼小辉丶的博客 8560

随机提取N条记录

随机提取10条记录的例子:Sql server:    select top 10 * from 表 order by newid()Access:    SELECT top 10 * FROM 表 ORDER BY Rnd(id) Rnd(id) 其中的id是自动编号字段,可以利用其他任何数值来完成比如用姓名字段(UserName)    SELECT top 10 * FROM 表 ORDE

编程岁月 1319

Copilot在游戏开发中的应用:Unity脚本自动生成实践

2021年GitHub Copilot的发布,为代码自动生成带来了革命性突破。作为基于GPT模型训练的AI辅助编程工具,Copilot能根据注释、函数名、代码上下文,实时生成符合语法和逻辑的代码片段,甚至完整脚本。减少重复劳动:自动生成模板代码(如生命周期、结构),让你专注核心逻辑;降低API学习成本:对Unity特有的组件(RigidbodyAnimator)、类(),Copilot能生成符合最佳实践的调用代码;统一代码风格:通过团队共享提示词模板,让生成的代码符合项目规范;快速原型迭代。

AIGC应用创新大全的博客 1618

IMSL CNL 7.0.0 (x86-64)Crack

IMSL CNL 7.0.0 (x86-64)Crack intel的算法库破解文件,这是C++版本的破解文件

随机提取10条记录

随机提取10条记录的例子: SQLServer:SelectTop10*From表OrderByNewID() Access:SelectTop10*From表OrderByRnd(ID) Rnd(ID)其中的ID是自动编号字段,可以利用其他任何数值来完成,比如用姓名字段(UserName) SelectTop10*From表OrderBYRnd(Len(UserName)) MySql:Sel...

happmaoo的专栏 300

Statistics and Machine Learning Toolbox

Statistics and Machine Learning Toolbox(带书签),MATLAB统计学习工具

随机提取记录的SQL例子,随机选择表格里的行

你可以使用很多种方式随机选择数据行;这在你想要往网站里加入动态特性的时候特别有效。例如,你可以随便选择一个产品,将其作为“今天的特色产品”来展示,或者质量评估人员(QA)可以生成一个随机的调用表,以测量用户的满意度。   但是其中的障碍是SQL不允许随机选择列。好消息是,有一个简单的技巧能够在SQL里实现这一功能。 该解决方案基于uniqueidentifier这个数据类型。唯一的标识符,也叫做全

编程岁月 2265

深度学习工具包 DeepLearningToolbox

深度学习工具包Deprecation notice.-----This toolbox is outdated and no longer maintained.There are much better tools available for deep learning than this toolbox, e.g. [Theano](http://deeplearning.net/software/theano/), [torch](http://torch.ch/) or [tensorflow](http://www.tensorflow.org/)I would suggest you use one of the tools mentioned above rather than use this toolbox.Best, Rasmus.DeepLearnToolbox================A Matlab toolbox for Deep Learning.Deep Learning is a new subfield of machine learning that focuses on learning deep hierarchical models of data.It is inspired by the human brain's apparent deep (layered, hierarchical) architecture.A good overview of the theory of Deep Learning theory is[Learning Deep Architectures for AI](http://www.iro.umontreal.ca/~bengioy/papers/ftml_book.pdf)For a more informal introduction, see the following videos by Geoffrey Hinton and Andrew Ng.* [The Next Generation of Neural Networks](http://www.youtube.com/watch?v=AyzOUbkUf3M) (Hinton, 2007)* [Recent Developments in Deep Learning](http://www.youtube.com/watch?v=VdIURAu1-aU) (Hinton, 2010)* [Unsupervised Feature Learning and Deep Learning](http://www.youtube.com/watch?v=ZmNOAtZIgIk) (Ng, 2011)If you use this toolbox in your research please cite [Prediction as a candidate for learning deep hierarchical models of data](http://www2.imm.dtu.dk/pubdb/views/publication_details.php?id=6284)```@MASTERSTHESIS\{IMM2012-06284, author = "R. B. Palm", title = "Prediction as a candidate for learning deep hierarchical models of data", year = "2012",}```Contact: rasmusbergpalm at gmail dot comDirectories included in the toolbox-----------------------------------`NN/` - A library for Feedforward Backpropagation Neural Networks`CNN/` - A library for Convolutional Neural Networks`DBN/` - A library for Deep Belief Networks`SAE/` - A library for Stacked Auto-Encoders`CAE/` - A library for Convolutional Auto-Encoders`util/` - Utility functions used by the libraries`data/` - Data used by the examples`tests/` - unit tests to verify toolbox is workingFor references on each library check REFS.mdSetup-----1. Download.2. addpath(genpath('DeepLearnToolbox'));Example: Deep Belief Network---------------------```matlabfunction test_example_DBNload mnist_uint8;train_x = double(train_x) / 255;test_x = double(test_x) / 255;train_y = double(train_y);test_y = double(test_y);%% ex1 train a 100 hidden unit RBM and visualize its weightsrand('state',0)dbn.sizes = [100];opts.numepochs = 1;opts.batchsize = 100;opts.momentum = 0;opts.alpha = 1;dbn = dbnsetup(dbn, train_x, opts);dbn = dbntrain(dbn, train_x, opts);figure; visualize(dbn.rbm{1}.W'); % Visualize the RBM weights%% ex2 train a 100-100 hidden unit DBN and use its weights to initialize a NNrand('state',0)%train dbndbn.sizes = [100 100];opts.numepochs = 1;opts.batchsize = 100;opts.momentum = 0;opts.alpha = 1;dbn = dbnsetup(dbn, train_x, opts);dbn = dbntrain(dbn, train_x, opts);%unfold dbn to nnnn = dbnunfoldtonn(dbn, 10);nn.activation_function = 'sigm';%train nnopts.numepochs = 1;opts.batchsize = 100;nn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.10, 'Too big error');```Example: Stacked Auto-Encoders---------------------```matlabfunction test_example_SAEload mnist_uint8;train_x = double(train_x)/255;test_x = double(test_x)/255;train_y = double(train_y);test_y = double(test_y);%% ex1 train a 100 hidden unit SDAE and use it to initialize a FFNN% Setup and train a stacked denoising autoencoder (SDAE)rand('state',0)sae = saesetup([784 100]);sae.ae{1}.activation_function = 'sigm';sae.ae{1}.learningRate = 1;sae.ae{1}.inputZeroMaskedFraction = 0.5;opts.numepochs = 1;opts.batchsize = 100;sae = saetrain(sae, train_x, opts);visualize(sae.ae{1}.W{1}(:,2:end)')% Use the SDAE to initialize a FFNNnn = nnsetup([784 100 10]);nn.activation_function = 'sigm';nn.learningRate = 1;nn.W{1} = sae.ae{1}.W{1};% Train the FFNNopts.numepochs = 1;opts.batchsize = 100;nn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.16, 'Too big error');```Example: Convolutional Neural Nets---------------------```matlabfunction test_example_CNNload mnist_uint8;train_x = double(reshape(train_x',28,28,60000))/255;test_x = double(reshape(test_x',28,28,10000))/255;train_y = double(train_y');test_y = double(test_y');%% ex1 Train a 6c-2s-12c-2s Convolutional neural network %will run 1 epoch in about 200 second and get around 11% error. %With 100 epochs you'll get around 1.2% errorrand('state',0)cnn.layers = { struct('type', 'i') %input layer struct('type', 'c', 'outputmaps', 6, 'kernelsize', 5) %convolution layer struct('type', 's', 'scale', 2) %sub sampling layer struct('type', 'c', 'outputmaps', 12, 'kernelsize', 5) %convolution layer struct('type', 's', 'scale', 2) %subsampling layer};cnn = cnnsetup(cnn, train_x, train_y);opts.alpha = 1;opts.batchsize = 50;opts.numepochs = 1;cnn = cnntrain(cnn, train_x, train_y, opts);[er, bad] = cnntest(cnn, test_x, test_y);%plot mean squared errorfigure; plot(cnn.rL);assert(er<0.12, 'Too big error');```Example: Neural Networks---------------------```matlabfunction test_example_NNload mnist_uint8;train_x = double(train_x) / 255;test_x = double(test_x) / 255;train_y = double(train_y);test_y = double(test_y);% normalize[train_x, mu, sigma] = zscore(train_x);test_x = normalize(test_x, mu, sigma);%% ex1 vanilla neural netrand('state',0)nn = nnsetup([784 100 10]);opts.numepochs = 1; % Number of full sweeps through dataopts.batchsize = 100; % Take a mean gradient step over this many samples[nn, L] = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.08, 'Too big error');%% ex2 neural net with L2 weight decayrand('state',0)nn = nnsetup([784 100 10]);nn.weightPenaltyL2 = 1e-4; % L2 weight decayopts.numepochs = 1; % Number of full sweeps through dataopts.batchsize = 100; % Take a mean gradient step over this many samplesnn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');%% ex3 neural net with dropoutrand('state',0)nn = nnsetup([784 100 10]);nn.dropoutFraction = 0.5; % Dropout fraction opts.numepochs = 1; % Number of full sweeps through dataopts.batchsize = 100; % Take a mean gradient step over this many samplesnn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');%% ex4 neural net with sigmoid activation functionrand('state',0)nn = nnsetup([784 100 10]);nn.activation_function = 'sigm'; % Sigmoid activation functionnn.learningRate = 1; % Sigm require a lower learning rateopts.numepochs = 1; % Number of full sweeps through dataopts.batchsize = 100; % Take a mean gradient step over this many samplesnn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');%% ex5 plotting functionalityrand('state',0)nn = nnsetup([784 20 10]);opts.numepochs = 5; % Number of full sweeps through datann.output = 'softmax'; % use softmax outputopts.batchsize = 1000; % Take a mean gradient step over this many samplesopts.plot = 1; % enable plottingnn = nntrain(nn, train_x, train_y, opts);[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');%% ex6 neural net with sigmoid activation and plotting of validation and training error% split training data into training and validation datavx = train_x(1:10000,:);tx = train_x(10001:end,:);vy = train_y(1:10000,:);ty = train_y(10001:end,:);rand('state',0)nn = nnsetup([784 20 10]); nn.output = 'softmax'; % use softmax outputopts.numepochs = 5; % Number of full sweeps through dataopts.batchsize = 1000; % Take a mean gradient step over this many samplesopts.plot = 1; % enable plottingnn = nntrain(nn, tx, ty, opts, vx, vy); % nntrain takes validation set as last two arguments (optionally)[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');```[![Bitdeli Badge](https://d2weczhvl823v0.cloudfront.net/rasmusbergpalm/deeplearntoolbox/trend.png)](https://bitdeli.com/free "Bitdeli Badge")

android 蓝牙通讯demo

android 下蓝牙通讯demo,实现了发现蓝牙,使能蓝牙,通过蓝牙发送消息。

从数据库中随机提取10条记录

Sql server: select top 10 * from 表 order by newid() Access: SELECT top 10 * FROM 表 ORDER BY Rnd(id) Rnd(id) 其中的id是自动编号字段,可以利用其他任何数值来完成 比如用姓名字段(UserName) SELECT top 10 * FROM 表 ORDER

bear_79的专栏 3442

随机提取N条记录[多种数据库方法]

<!--google_ad_client = "pub-4490194096475053";/* 内容页,300x250,第一屏 */google_ad_slot = "3685991503";google_ad_width = 300;google_ad_height = 250;//--><script type="text/javascript"src="

管子(zero)的杂乱空间 1477

mysql 所有记录中随机取5条

select * from word_video_information order by rand() limit 5;  

心有猛虎 细嗅蔷薇 1万+
上一篇: 批量添加类例子
下一篇: C#多线程
web718
博客等级 码龄22年 34粉丝 280原创
评论
成就一亿技术人!
拼手气红包6.0元
还能输入1000个字符
 
 条评论被折叠 查看
添加红包

请填写红包祝福语或标题

个

红包个数最小为10个

元

红包金额最低5元

当前余额3.43元 前往充值 >
需支付:10.00元
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付元
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值