Course Introduction：Tips for combining multiple rows of data into one row in SQL include: using the CONCAT function to connect strings, such as dividing names into full names. Use the GROUP_CONCAT function to connect the values ??of all rows in the group, such as grouping the product list. Use the STRING_AGG function to connect strings and specify delimiters, such as grouping skill lists and adding delimiters. Use the FOR XML PATH('') clause to convert the query results to an XML string. Use the STUFF function to insert substrings, such as converting the customer name to a line with an XML tag.
2025-04-10 comment 0 762
Course Introduction：The function of Angular routing is to realize page jump and view switching in single-page applications. 1. The basic routing function can be realized by introducing RouterModule and Routes, configuring the routing table in the root module or using lazy loading method to load in modules; 2. Use the router-outlet tag to specify the display location of the routing component, and implement local page updates through the routerLink instruction; 3. Dynamic routing can be defined by adding parameters (such as /user/:id) to the path and injecting ActivatedRoute into the component; 4. Nested routing defines the child routing structure through the children attribute, and the parent component needs to add router-outlet to
2025-07-04 comment 0 885
Course Introduction：Fragments is a function in Vue3 that allows components to return multiple root nodes. In Vue2, everything must be wrapped with a single element. 1.Fragments allows components to directly return multiple parallel nodes, such as the sum does not need to be wrapped in the parent element; 2. It improves structural semantics, avoids unnecessary nesting, optimizes layout and performance; 3. Simple usage, just write multiple top-level nodes directly under the tag; 4. Notes include ref management problems caused by the lack of unified parent nodes, scoped style scope impact, and Transition animation restrictions, which are usually solved by manually processing refs or adding package containers.
2025-07-17 comment 0 883
Course Introduction：Native lazy loading is a built-in browser function that enables lazy loading of pictures by adding loading="lazy" attribute to the tag. 1. It does not require JavaScript or third-party libraries, and is used directly in HTML; 2. It is suitable for pictures that are not displayed on the first screen below the page, picture gallery scrolling add-ons and large picture resources; 3. It is not suitable for pictures with first screen or display:none; 4. When using it, a suitable placeholder should be set to avoid layout jitter; 5. It should optimize responsive image loading in combination with srcset and sizes attributes; 6. Compatibility issues need to be considered. Some old browsers do not support it. They can be used through feature detection and combined with JavaScript solutions.
2025-07-12 comment 0 827
Course Introduction：SqlParameter Parameters.Add vs. AddWithValue: Choosing the Best MethodWhen working with SQL commands, you may encounter the need to add...
2025-01-10 comment 0 669
Course Elementary 13770
Course Introduction：Scala Tutorial Scala is a multi-paradigm programming language, designed to integrate various features of object-oriented programming and functional programming.
Course Elementary 82279
Course Introduction："CSS Online Manual" is the official CSS online reference manual. This CSS online development manual contains various CSS properties, definitions, usage methods, example operations, etc. It is an indispensable online query manual for WEB programming learners and developers! CSS: Cascading Style Sheets (English full name: Cascading Style Sheets) is an application used to express HTML (Standard Universal Markup Language).
Course Elementary 13143
Course Introduction：SVG is a markup language for vector graphics in HTML5. It maintains powerful drawing capabilities and at the same time has a very high-end interface to operate graphics by directly operating Dom nodes. This "SVG Tutorial" is intended to allow students to master the SVG language and some of its corresponding APIs, combined with the knowledge of 2D drawing, so that students can render and control complex graphics on the page.
Course Elementary 24589
Course Introduction：In the "AngularJS Chinese Reference Manual", AngularJS extends HTML with new attributes and expressions. AngularJS can build a single page application (SPAs: Single Page Applications). AngularJS is very easy to learn.
Course Elementary 27446
Course Introduction：Go is a new language, a concurrent, garbage-collected, fast-compiled language. It can compile a large Go program in a few seconds on a single computer. Go provides a model for software construction that makes dependency analysis easier and avoids most C-style include files and library headers. Go is a statically typed language, and its type system has no hierarchy. Therefore users do not need to spend time defining relationships between types, which feels more lightweight than typical object-oriented languages. Go is a completely garbage-collected language and provides basic support for concurrent execution and communication. By its design, Go is intended to provide a method for constructing system software on multi-core machines.
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