php操作MYSQL 语句条件是越多越好还是越少越好呢,该如何处理
php操作MYSQL 语句条件是越多越好还是越少越好呢
问一下
假如现在想update一下
sql1="update table set aa=aa where id=1";
sql2="update table set aa=aa where id=1 and classid=12 and infoid=1";
delete:
sql1="delete from table where id=1";
sql2="delete from table where id=1 and classid=12 and infoid=1";
请问一下update时 sql1和sql2哪个更好些
delete时 sql1和sql2哪个更好些
请说一下原因,谢谢。
------解决方案--------------------
那你就不需要提这个问题了嘛...明显是老鸨(Mysql)给你筛选一下就可以了。要不那些判断条件是做啥用的,我倒...相对来说条件越精确执行的效率越高,结果就精确,当然前提是你的索引,以及SQL语句的写法要正确。很多时候条件没写好反而起反作用。
2,和老鸨子讲一下,身高要170的,上围要80的,把符合这些条件的小姐喊来,然后再从符合这些条件的里面找个叫 如花 的
这个时候老鸨子果断给你找了个如花,在你一番XXOO之后 你发现.... 他奶奶的居然是个变性人! 所以 你的条件一定要弄对。哈哈哈

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics



Google Chrome is one of the most popular browsers in the world and many users prefer to use it as the default browser on their Windows PCs. Chrome offers a wide range of features that make the browsing experience enjoyable and effortless, and therefore, it remains one of the most trusted browsers. But just like any other browser, even Chrome has its own shortcomings, and it's equally prone to bugs and glitches when you need it most. One such error is Error Code 3: 0x80040154, which occurs while checking for Google Chrome updates. The error message reads "An error occurred while checking for updates. The update check failed to start (Error code 3: 0x80080005) or (Error

There are two keyboard delete keys: del (delete) key and backspace key. Backspace is also called the backspace key. This key can delete the text content in front of the cursor; and the delete key can delete characters, files and selected objects. Each time you press the del key, a character to the right of the cursor will be deleted, and the character to the right of the cursor will move one frame to the left; when one or more files/folders are selected, press the Del key to quickly delete; in some applications Select an object in the program and press the Del key to quickly delete the selected object.

The functions of the delete key are: 1. Delete characters; each time the delete key is pressed, a character to the right of the cursor will be deleted, and the character to the right of the cursor will move one frame to the left. 2. Delete files; when one or more files/folders are selected, press the Delete key to quickly delete them (move to the Recycle Bin for recovery). 3. Delete the selected object; select an object in some applications and press the Delete key to quickly delete the selected object.

If you are using Visual Studio Code (VSCode) and thinking about how to disable its automatic software updates and how to disable the automatic updates of its extensions, then read this article. If you don't use VSCode often, open the editor after a long period of time and want to enable automatic updates, this article will also guide you in doing so. Let us discuss in detail the different ways to enable or disable VSCode automatic updates. Table of Contents Method One: Use Settings to Enable/Disable VSCode Automatic Updates Step 1: Open VS Code and click the gear-shaped symbol in the lower left corner. Step 2: Click Settings in the list that appears. Step 3: Type update in the search bar and hit enter. Find Updates: Pattern 4

After several pre-releases, the KDE Plasma development team unveiled version 6.0 of its desktop environment for Linux and BSD systems on 28 February, using the Qt6 framework for the first time. KDE Plasma 6.1 now comes with a number of new features t

When we use the win10 system, we sometimes encounter situations where the computer becomes stuck. Then when we check the background process, we find that a Microsoftcompatibilitytelemetry process takes up a particularly high amount of resources. So what is going on? Users can try to uninstall the third-party protection software and then try a clean boot to operate. Let this site carefully introduce to users the solution to the high CPU usage of Microsoftcompatibilitytelemetry. Solution to the high CPU usage of Microsoftcompatibilitytelemetry Method 1: Try after uninstalling the third-party protection software

Control+Alt+Delete: "Mac" mode Ctrlaltdel is a common key combination used by Windows users to open Task Manager. They usually exit unwanted applications from the manager menu to free up some space on their computer. The Control+Alt+Delete Mac variant lets you open the Force Quit menu. If Mac users want to quit the program causing the problem or view open programs, they can interact with the menu to investigate further. How to perform ControlAltDelete on Mac? If you have any malfunctioning applications, you must use this key combination to

SQLUPDATE statement The Update statement is used to modify the data in the table. The syntax is as follows: UPDATE table name SET column name = new value WHERE column name = certain value "Person" table: LastNameFirstNameAddressCityGatesBillXuanwumen10BeijingWilsonChamps-Elysees Update a column in a certain row UPDATEPerson SETFirstName="Fred" WHERELastName="Wilson" Result: LastNa
