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General syntax: DATEDIFF (datepart, datetime_expr1, datetime_expr2) It will return a positive number if datetime_expr is in the past relative to datetime_expr2, and a negative number otherwise. Examples DECLARE @now DATETIME2 = GETDATE(); DECLARE @oneYearAgo DATETIME2 = DATEADD(YEAR, -1, @now...

DATEPART returns the specified datepart of the specified datetime expression as a numeric value. DATENAME returns a character string that represents the specified datepart of the specified date. In practice DATENAME is mostly useful for getting the name of the month or the day of the week. There a...

A CSS rule consists of a selector (e.g. h1) and declaration block ({}). h1 {}

The most basic instance of an if construct evaluates a condition and executes some code according to the condition outcome. If the condition returns true, the code within the conditional is executed. counter = 10 if counter is 10 console.log 'This will be executed!' The if construct can be e...

To start using Spring data JPA, you must include the dependency in your project with the one of Spring core, all together. If you're using Maven as dependency management system (replace version-number for the version you want to use): <dependencies> <dependency> <groupI...

Mysql has its EVENT functionality for avoiding complicated cron interactions when much of what you are scheduling is SQL related, and less file related. See the Manual page here. Think of Events as Stored Procedures that are scheduled to run on recurring intervals. To save time in debugging Event-r...

An array column is supported by PostgreSQL. Rails will automatically convert a PostgreSQL array to a Ruby array, and vice-versa. Create a table with an array column: create_table :products do |t| t.string :name t.text :colors, array: true, default: [] end Add an array column to an existi...

Make sure your tomcat configurations file, server.xml has this line: <Connector port="8443" protocol="org.apache.coyote.http11.Http11Protocol" maxHttpHeaderSize="8192" SSLEnabled="true" maxThreads="150" minSpareThrea...

PHP 5.5 introduces Generators and the yield keyword, which allows us to write asynchronous code that looks more like synchronous code. The yield expression is responsible for giving control back to the calling code and providing a point of resumption at that place. One can send a value along the yi...

Using .NET's rich reflection APIs, you can gain access to an assembly's metadata. For example, you can get this assembly's title attribute with the following code using System.Linq; using System.Reflection; ... Assembly assembly = typeof(this).Assembly; var titleAttribute = assembly.GetCust...

Iterators produce enumerators. In C#, enumerators are produced by defining methods, properties or indexers that contain yield statements. Most methods will return control to their caller through normal return statements, which disposes all state local to that method. In contrast, methods that use y...

Codeigniter may be configured to run more than one project without duplicating CI core files. It's possible by splitting CI Application side. For example let's take project of website, which contains front-end and back-end Content Management System (CMS) applications. In this case CI folder struct...

Your code in source control has version numbers either by default (SVN ids or Git SHA1 hashes) or explicitly (Git tags). Rather than manually updating versions in AssemblyInfo.cs you can use a build time process to write the version from your source control system into your AssemblyInfo.cs files and...

Publications can be merged on the client, resulting in differently shaped documents within a single cursor. The following example represents how a user directory might publish a minimal amount of public data for users of an app, and provide a more detailed profile for the logged in user. // client...

Then go into the mongo shell and initiate the replica set, like so: meteor mongo > rs.initiate() PRIMARY> rs.add("mongo-a") PRIMARY> rs.add("mongo-b") PRIMARY> rs.add("mongo-c") PRIMARY> rs.setReadPref('secondaryPreferred')

General Using the package RMySQL we can easily query MySQL as well as MariaDB databases and store the result in an R dataframe: library(RMySQL) mydb <- dbConnect(MySQL(), user='user', password='password', dbname='dbname',host='127.0.0.1') queryString <- "SELECT * FROM table1 t1 JO...

Knitr is an R package that allows us to intermingle R code with LaTeX code. One way to achieve this is external code chunks. External code chunks allow us to develop/test R Scripts in an R development environment and then include the results in a report. It is a powerful organizational technique....

Instead of struct IShape { virtual ~IShape() = default; virtual void print() const = 0; virtual double area() const = 0; virtual double perimeter() const = 0; // .. and so on }; Visitors can be used: // The concrete shapes struct Square; struct Circle; // The v...

Paste your fonts file inside android/app/src/main/assets/fonts/font_name.ttf Recompile the Android app by running react-native run-android Now, You can use fontFamily: 'font_name' in your React Native Styles

Similar to currying, partial application is used to reduce the number of arguments passed to a function. Unlike currying, the number need not go down by one. Example: This function ... function multiplyThenAdd(a, b, c) { return a * b + c; } ... can be used to create another function that...