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Articles on Trending Technologies
Technical articles with clear explanations and examples
MySQL - SUM rows with same ID?
To sum rows with same ID, use the GROUP BY HAVING clause.Let us create a table −Examplemysql> create table demo84 -> ( -> id int, -> price int -> ) -> ; Query OK, 0 rows affected (0.60Insert some records into the table with the help of insert command −Examplemysql> insert into demo84 values(1, 2000); Query OK, 1 row affected (0.08 mysql> insert into demo84 values(1, 2000); Query OK, 1 row affected (0.14 mysql> insert into demo84 values(2, 1800); Query OK, 1 row affected (0.14 mysql> insert into demo84 values(2, 2200); Query ...
Read MoreShow date like 30-04-2020 instead of 2020-04-30 from MySQL database?
For this, use DATE_FORMAT() in MySQL. The syntax is as follows −Exampleselect date_format(yourColumnName, '%d-%m-%Y') as anyAliasName from yourTableName;Let us create a table −Examplemysql> create table demo80 -> ( -> due_date date -> ); Query OK, 0 rows affected (0.74Insert some records into the table with the help of insert command −Examplemysql> insert into demo80 values('2020-04-30'); Query OK, 1 row affected (0.14 mysql> insert into demo80 values('2016-01-10'); Query OK, 1 row affected (0.17 mysql> insert into demo80 values('2018-03-21'); Query OK, 1 row affected (0.12Display records from the table using select statement −Examplemysql> select *from demo80;This will ...
Read MoreHow to get username using ID from another table in MySQL database?
To get username using ID from two tables, you need to use JOIN and join the tables.Let us create a table −Examplemysql> create table demo77 -> ( -> userid int not null primary key, -> username varchar(20) -> ); Query OK, 0 rows affected (2.63Insert some records into the table with the help of insert command −Examplemysql> insert into demo77 values(1, 'John'); Query OK, 1 row affected (0.19 mysql> insert into demo77 values(2, 'Bob'); Query OK, 1 row affected (0.36Display records from the table using select statement −Examplemysql> select *from demo77;This will produce the following ...
Read MoreFind all users with a unique last name in MySQL?
To find all users with unique last name, use GROUP BY HAVING COUNT().Let us create a table −Examplemysql> create table demo76 -> ( -> firstName varchar(20), -> lastName varchar(20) -> ); Query OK, 0 rows affected (9.29Insert some records into the table with the help of insert command −Examplemysql> insert into demo76 values('John', 'Doe'); Query OK, 1 row affected (2.52 mysql> insert into demo76 values('David', 'Smith'); Query OK, 1 row affected (6.31 mysql> insert into demo76 values('Adam', 'Smith'); Query OK, 1 row affected (1.52Display records from the table using select statement −Examplemysql> select *from ...
Read MoreFetching rows updated at timestamp older than 1 day in MySQL?
For this, yYou can use from_unixtime() along with now().Let us create a table with some data type −Examplemysql> create table demo75 -> ( -> due_date int(11) -> ); Query OK, 0 rows affected, 1 warning (2.87Insert some records into the table with the help of insert command −Examplemysql> insert into demo75 values(unix_timestamp("2020-01-10")); Query OK, 1 row affected (0.46 mysql> insert into demo75 values(unix_timestamp("2020-11-19")); Query OK, 1 row affected (0.59 mysql> insert into demo75 values(unix_timestamp("2020-12-18")); Query OK, 1 row affected (0.44 mysql> insert into demo75 values(unix_timestamp("2020-11-10")); Query OK, 1 row affected (0.70Display records from the ...
Read MoreMySQL LIKE query with dynamic array?
To implement LIKE query with dynamic array, the syntax is as follows −Exampleselect *from yourTableName where yourColumnName2 like "%yourValue%" order by yourColumnName1 asc limit yourLimitValue;Let us create a table −Examplemysql> create table demo74 -> ( -> user_id int not null auto_increment primary key, -> user_names varchar(250) -> ) -> ; Query OK, 0 rows affected (0.67Insert some records into the table with the help of insert command −Examplemysql> insert into demo74(user_names) values("John Smith1, John Smith2, John Smith3"); Query OK, 1 row affected (0.18 mysql> insert into demo74(user_names) values("John Smith1"); Query OK, ...
Read MoreExplain what a neuron is, in terms of Neural Network in Machine Learning.
A neuron is a mathematical function that takes one or more values as input and outputs a ingle numerical value −It can be defined as follows −Here, ‘f’ refers to the function.We first computed the weighted sum of the inputs xi and the weights wiThe weight wi is also known as the activation value or activation function.The input xi can be a numerical value that represents the input data or it can be an output from other neurons if the neuron belong to a neural network.The weight wi is a numerical value that can be used to represent the strength ...
Read MoreWhat is a Neural Network in Machine Learning?
A neural network can be understood as a network of hidden layers, an input layer and an output layer that tries to mimic the working of a human brain.The hidden layers can be visualized as an abstract representation of the input data itself. These layers help the neural network understand various features of the data with the help of its own internal logic.These neural networks are non-interpretable models. Non-interpretable models are those which can’t be interpreted or understood even if we observe the hidden layers. This is because the neural networks have an internal logic working on its own, that ...
Read MoreWhat is a Perceptron? What are its limitations? How can these limitations be overcome in Machine Learning?
The basic example of a neural network is a ‘perceptron’. It was invented by Frank Rosenblatt in 1957. The perceptron is a classification algorithm similar to logistic regression. This because, similar to logistic regression, a perceptron has weights, w, and an output function, ‘f’, which is a dot product of the weights and the input.The only difference is that ‘f’ is a simple step function, where a logistic regression rule is applied to the output of the logistic function. On the other hand, perceptron can be understood as an example of a simple one-layer neural feedforward network.The perceptron was considered ...
Read MoreWhy are Neural Networks needed in Machine Learning?
Neural networks have been around for many years, through which they have been praised as well as criticised for their characteristics.But off late, they have gained attention over other machine learning algorithms. Of course, Machine learning algorithms are important as they help achieve certain goals. But what should we do when machine learning algorithms can’t achieve higher accuracy?This is where deep learning algorithms come into play. They mimic the layers of the human brain, and try to take optimal decisions by passing an input from one layer to the next.Neural networks, as the name suggests, tries to follow the pattern ...
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