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Course Introduction：InmodernSQLdatabases,COUNT(),COUNT(1),andCOUNT(column_name)havelittletonoperformancedifferenceinbasicqueries.1.COUNT()countsallrows,includingNULLs,andisbestfortotalrowcount.2.COUNT(1)behavesthesameasCOUNT(),withnoperformanceadvantage,andisusedmainlyb

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Course Introduction：Understanding the Difference between COUNT(*) and COUNT(column_name)MySQL provides two count functions: COUNT(*) and COUNT(column_name). Both...

2024-11-21 comment 0  1196

Course Introduction：When to Use COUNT(*) vs. COUNT(column-name)In SQL, both COUNT(*) and COUNT(column-name) are commonly used aggregate functions to count the number...

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Course Introduction：Understanding the Differences Between COUNT(*) and COUNT(column_name)In MySQL, the COUNT(*) and COUNT(column_name) functions play crucial roles in...

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Course Introduction：COUNT(*) vs COUNT(column_name): Understanding the Differences in MySQLIn MySQL, the COUNT() function provides a convenient way to count the number...

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Course Elementary  13826

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  82370

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  13185

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  24635

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  27493

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.