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2023年1月22日
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# 作 者 : 繁 华 倾 夏
# 力扣(LeetCode):183. 从不订购的客户
# MySQL 数据库
# 使用嵌套语句
select name as Customers
from Customers
where Id not in(select CustomerId from Orders)
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# 作 者 : 繁 华 倾 夏
# 力扣(LeetCode):183. 从不订购的客户
# MySQL 数据库
# 使用嵌套语句
select name as Customers
from Customers
where Id not in(select CustomerId from Orders)
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【力扣MySQL】183. 从不订购的客户
看懂这两个表后题目就可以理解成“找到Customers.id不在Orders.customerId的Customers.name”最后那个as 'Customers'要加,不然是不会过的。看来这两位就是工资没有员工高的经理吧。不订购是怎么成为客户的?
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MySQL之LeetCode-183(从不订购的客户)
题目(简单) 某网站包含两个表,Customers 表和 Orders 表。编写一个 SQL 查询,找出所有从不订购任何东西的客户。 Customers 表: ±—±------+ | Id | Name | ±—±------+ | 1 | Joe | | 2 | Henry | | 3 | Sam | | 4 | Max | ±—±------+ Orders 表: ±—...
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LeetCode-MySQL-183. 从不订购的客户
某网站包含两个表,Customers 表和 Orders 表。编写一个 SQL 查询,找出所有从不订购任何东西的客户。 Customers 表: +----+-------+ | Id | Name | +----+-------+ | 1 | Joe | | 2 | Henry | | 3 | Sam | | 4 | Max | +----+-------+ Or...
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#力扣 MySQL:183. 从不订购的客户 @FDDLC
题目描述: 183. 从不订购的客户 - 力扣(LeetCode) (leetcode-cn.com) SQL: select Name Customers from Customers where id not in (select CustomerId from Orders) SQL2: select Name Customers from Customers c left join Orders o on c.Id=o.CustomerId where o.Customer..
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LeetCode 183. 从不订购的客户【mysql】
183. 从不订购的客户 题意: 某网站包含两个表,Customers 表和 Orders 表。编写一个 SQL 查询,找出所有从不订购任何东西的客户。 Customers 表: +----+-------+ | Id | Name | +----+-------+ | 1 | Joe | | 2 | Henry | | 3 | Sam | | 4 | Max | +----+-------+ Orders 表: +----+------------+ | Id | Custome
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【力扣日记】【MySQL】183 从不订购的客户
某网站包含两个表,Customers 表和 Orders 表。编写一个 SQL 查询,找出所有从不订购任何东西的客户。 Customers 表: +----+-------+ | Id | Name | +----+-------+ | 1 | Joe | | 2 | Henry | | 3 | Sam | | 4 | Max | +----+-------+ Orders ...
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[mysql]leetcode183:从不订购的客户(easy)
题目: 183. 从不订购的客户 代码如下:: # Write your MySQL query statement below -- 过滤条件:Customers表的顾客id不在Order表的CustomerId就行了 select Customers.name as 'Customers' from Customers where Customers.id not in ( ...
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]); 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Leetcode-Mysql题目及知识点总结(183.从不订购的客户)
计算机小白QAQ,因为想找数分岗暑期实习所以充了会员想集中刷一下leetcode的mysql部分。写这个系列博文和大家们交流一下,后面也会持续更新面经准备的一些问题,欢迎同好们一起交流,求大佬轻喷QAQ。因为自己初学也走了很多弯路,所以会尽量写得详细一点,如果可以帮助到后来的朋友们,请各位留言鼓励一下哈哈哈哈。 183、从不订购的客户 思路1:利用左连接,将order中的customerid和customers中的id匹配,匹配不到的证明是没有购买东西的用户。 selectNameasCus...
leetcode、mysql 183. 从不订购的客户
某网站包含两个表,Customers 表和 Orders 表。编写一个 SQL 查询,找出所有从不订购任何东西的客户。 Customers 表: +----+-------+ | Id | Name | +----+-------+ | 1 | Joe | | 2 | Henry | | 3 | Sam | | 4 | Max | +----+-------+ Orders 表: +----+------------+ | Id | CustomerId | +----+--..
MySQL leetcode刷题 (7):183. 从不订购的客户
题目描述: 某网站包含两个表,Customers 表和 Orders 表。编写一个 SQL 查询,找出所有从不订购任何东西的客户。 Customers 表: ±—±------+ | Id | Name | ±—±------+ | 1 | Joe | | 2 | Henry | | 3 | Sam | | 4 | Max | ±—±------+ Orders 表: ±—±...
LeetCode183-MySQL-从不订购的客户
某网站包含两个表,Customers 表和 Orders 表。编写一个 SQL 查询,找出所有从不订购任何东西的客户。Customers 表:+----+-------+ | Id | Name | +----+-------+ | 1 | Joe | | 2 | Henry | | 3 | Sam | | 4 | Max | +----+-------+ Orders 表:...
LeetCode 183从不订购的客户(MySQL)
4 从不订购的客户 select c.Name as Customers from Customers c where id not in (select c.id from Customers c join Orders o on o.CustomerId = c.id);
LeetCode刷题-数据库(MySQL)- 183.从不订购的客户
183.从不订购的客户 一、题目描述 某网站包含两个表,Customers表和Orders表。编写一个SQL查询,找出所有从不订购任何东西的客户。 Customers表: Id Name 1 Joe 2 Henry 3 Sam 4 Max Orders表: Id CustomerId 1 3 2 1 例如给定上述表格,你的查询应返回: ...
Leetcode Mysql 183. 从不订购的客户(DAY 18)
文章目录原题题目代码实现(首刷自解) 原题题目 代码实现(首刷自解) # Write your MySQL query statement below SELECT name AS customers FROM customers WHERE id NOT IN (SELECT customerid FROM Orders)
Leetcode-MySQL(183. 从不订购的客户)
从不订购的客户:某网站包含两个表,Customers 表和 Orders 表。编写一个 SQL 查询,找出所有从不订购任何东西的客户。 # Write your MySQL query statement below SELECT Customers.Name as Customers FROM Customers LEFT JOIN orders on Customers.Id <=> orders.CustomerId WHERE orders.CustomerId IS NULL;.
leetcode mysql题库解答 183. 从不订购的客户
select name Customers from Customers cwhere c.id not in (select customerId from Orders)
mysql报警代码183_Leetcode-Mysql题目及知识点总结(183.从不订购的客户)
计算机小白QAQ,因为想找数分岗暑期实习所以充了会员想集中刷一下leetcode的mysql部分。写这个系列博文和大家们交流一下,后面也会持续更新面经准备的一些问题,欢迎同好们一起交流,求大佬轻喷QAQ。因为自己初学也走了很多弯路,所以会尽量写得详细一点,如果可以帮助到后来的朋友们,请各位留言鼓励一下哈哈哈哈。183、从不订购的客户 思路1:利用左连接,将order中的customerid和cus...
LeetCode183之从不订购的客户(MySQL实现)
一、题目 二、一种解题思路 1)核心:根据Customers表中的Id对比CustomerId有的,只要是不存在的就返回。 时间复杂度:O(n) 空间复杂度:O(1) 2)核心代码: select Name Customers from Customers where Customers.Id not in ( select CustomerId ...
LeetCode(183)—— 从不订购的客户(MySQL)
某网站包含两个表,Customers 表和 Orders 表。编写一个 SQL 查询,找出所有从不订购任何东西的客户。 Customers 表: Id Name 1 Joe 2 Henry 3 Sam 4 Max Orders 表: Id CustomerId 1 3 2 1 例如给定上述表格,你的查询应返回: Customers ...
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