SQL查询中的{}是干吗的
SQL查询中的{}是干什么的？
$sqlstr="select name from user where id='{$row[0]}'";
我同学写的代码，请问里边的{}起到什么作用了？
多谢~~
------最佳解决方案--------------------
在""表示的字符串中，用{变量}来表示引用一个变量的值，当然实际上大部分情况下不加大括号也能正常使用，不过加上大括号是个很好的习惯
------其他解决方案--------------------
就是声明这是一个变量，因为有时候“”和‘’混排会出错，这样避免了
------其他解决方案--------------------
这个基本都是用于包围变量的，能安全的让变量在字符串中当真正的变量来用
------其他解决方案--------------------
区别不大，一个是不戴安全帽修房子，一个是戴着安全帽修房子！！
------其他解决方案--------------------
被花括号“{}”括起的内容表示是一个整体
凡是有可能出现歧义的地方都应该用花括号“{}”括起
比如你示例的代码中、条件语句分支中的多行代码，等等
------其他解决方案--------------------
{} 其实就是一个区块，一个整体．
------其他解决方案--------------------
这跟SQL没关系的，作用楼上各位都解释了
------其他解决方案--------------------
貌似没有多少关系。
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
Solution: Your organization requires you to change your PIN
Oct 04, 2023 pm 05:45 PM
The message "Your organization has asked you to change your PIN" will appear on the login screen. This happens when the PIN expiration limit is reached on a computer using organization-based account settings, where they have control over personal devices. However, if you set up Windows using a personal account, the error message should ideally not appear. Although this is not always the case. Most users who encounter errors report using their personal accounts. Why does my organization ask me to change my PIN on Windows 11? It's possible that your account is associated with an organization, and your primary approach should be to verify this. Contacting your domain administrator can help! Additionally, misconfigured local policy settings or incorrect registry keys can cause errors. Right now
What is the difference between HQL and SQL in Hibernate framework?
Apr 17, 2024 pm 02:57 PM
HQL and SQL are compared in the Hibernate framework: HQL (1. Object-oriented syntax, 2. Database-independent queries, 3. Type safety), while SQL directly operates the database (1. Database-independent standards, 2. Complex executable queries and data manipulation).
10 Ways to Adjust Brightness on Windows 11
Dec 18, 2023 pm 02:21 PM
Screen brightness is an integral part of using modern computing devices, especially when you look at the screen for long periods of time. It helps you reduce eye strain, improve legibility, and view content easily and efficiently. However, depending on your settings, it can sometimes be difficult to manage brightness, especially on Windows 11 with the new UI changes. If you're having trouble adjusting brightness, here are all the ways to manage brightness on Windows 11. How to Change Brightness on Windows 11 [10 Ways Explained] Single monitor users can use the following methods to adjust brightness on Windows 11. This includes desktop systems using a single monitor as well as laptops. let's start. Method 1: Use the Action Center The Action Center is accessible
How to turn off private browsing authentication for iPhone in Safari?
Nov 29, 2023 pm 11:21 PM
In iOS 17, Apple introduced several new privacy and security features to its mobile operating system, one of which is the ability to require two-step authentication for private browsing tabs in Safari. Here's how it works and how to turn it off. On an iPhone or iPad running iOS 17 or iPadOS 17, Apple's browser now requires Face ID/Touch ID authentication or a passcode if you have any Private Browsing tab open in Safari and then exit the session or app to access them again. In other words, if someone gets their hands on your iPhone or iPad while it's unlocked, they still won't be able to view your privacy without knowing your passcode
Usage of division operation in Oracle SQL
Mar 10, 2024 pm 03:06 PM
"Usage of Division Operation in OracleSQL" In OracleSQL, division operation is one of the common mathematical operations. During data query and processing, division operations can help us calculate the ratio between fields or derive the logical relationship between specific values. This article will introduce the usage of division operation in OracleSQL and provide specific code examples. 1. Two ways of division operations in OracleSQL In OracleSQL, division operations can be performed in two different ways.
Win10/11 digital activation script MAS version 2.2 re-supports digital activation
Oct 16, 2023 am 08:13 AM
The famous activation script MAS2.2 version supports digital activation again. The method originated from @asdcorp and the team. The MAS author calls it HWID2. Download gatherosstate.exe (not original, modified) from https://github.com/massgravel/Microsoft-Activation-Scripts, run it with parameters, and generate GenuineTicket.xml. First take a look at the original method: gatherosstate.exePfn=xxxxxxx;DownlevelGenuineState=1 and then compare with the latest method: gatheros
Comparison and differences of SQL syntax between Oracle and DB2
Mar 11, 2024 pm 12:09 PM
Oracle and DB2 are two commonly used relational database management systems, each of which has its own unique SQL syntax and characteristics. This article will compare and differ between the SQL syntax of Oracle and DB2, and provide specific code examples. Database connection In Oracle, use the following statement to connect to the database: CONNECTusername/password@database. In DB2, the statement to connect to the database is as follows: CONNECTTOdataba
What does the identity attribute in SQL mean?
Feb 19, 2024 am 11:24 AM
What is Identity in SQL? Specific code examples are needed. In SQL, Identity is a special data type used to generate auto-incrementing numbers. It is often used to uniquely identify each row of data in a table. The Identity column is often used in conjunction with the primary key column to ensure that each record has a unique identifier. This article will detail how to use Identity and some practical code examples. The basic way to use Identity is to use Identit when creating a table.
