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Course Introduction：Dynamic SQL is a SQL statement dynamically built during the program operation process, which is used to implement flexible query logic. It splices SQL according to runtime conditions and is suitable for scenarios such as multi-condition query, dynamic sorting, batch operations, etc. When using it, SQL injection should be prevented through parameterized queries, whitelist verification, query constructor, etc. 1. Multi-condition query should determine whether the parameters exist and dynamically add WHERE conditions; 2. Dynamic sorting requires verification of column names and restricting paging parameters; 3. Batch operations should control the length of the parameter and use transactions. In addition, loop splicing, generating complex statements should be avoided, and execution plans should be checked using EXPLAIN to optimize performance. Rational use of dynamic SQL can improve flexibility, but it requires both security and efficiency.

2025-07-28 comment 0  617

Course Introduction：Single-condition filtering can be implemented using boolean index, such as df[df['score']>80] filtering rows with scores greater than 80; 2. Multi-condition filtering requires connections of & (and) and | (or) and enclosing each condition in parentheses, such as (df['age']>22)&(df['score']>85), or isin() to match enumeration values; 3. Fuzzy string matching can be implemented through str.contains(), such as df[df['name'].str.contains('a',case=False)] filtering rows with names containing 'a'; 4. The query() method provides a more concise syntax and supports expressions

2025-07-31 comment 0  187

Course Introduction：In MySQL query, IF statements can be used to return different values in SELECT according to the conditions, which are suitable for data judgment, classification or formatted output. IF(condition,value_if_true,value_if_false) is its basic structure; for example, IF(status=1,'completed','not completed') converts numbers into intuitive tags; it can be used in combination with other fields, such as IF(amount>1000,'large order','ordinary order') to classify orders; support nesting to achieve multi-condition judgments, such as IF(score>=90,'A',IF(score>=80,'B','C')); compared to CAS

2025-07-18 comment 0  867

Course Introduction：Five super cool jQuery touch sliding picture library plug-ins are recommended to help you display your products or portfolios in a wonderful way! Users can swipe up and down, left and right to switch pictures, which is worth a try! Related articles: 30 Best Free Android Media Players Add jQuery drag/touch support for iPad Hammer.js touch carousel diagram A JavaScript library for multi-touch gestures. Source code demonstration 2. TouchSwipe TouchSwipe is a jQuery plug-in that can be used with jQuery on touch devices such as iPad and iPhone. Source code demonstration 3. TouchWipe Allows you to use iPhone, iPad or i

2025-02-23 comment 0  1024

Course Introduction：Container query solves the context dependency problem of traditional media queries by letting components respond according to the parent container size rather than the viewport size. 1. First, use container-type or container-name to define the query container, 2. Then use @container to write conditional styles instead of @media, so that components are adaptable in different layouts, supporting nested, multi-condition and named containers, suitable for grid, CMS and design systems. Modern browsers have good support, truly realizing component-level responsive design.

2025-07-25 comment 0  736

Course Elementary  13819

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  82352

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  13173

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  24624

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  27483

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.