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Editor to share with you what is not equal to the way in sql, I believe that most people do not know much about it, so share this article for your reference, I hope you will learn a lot after reading this article, let's go to know it!

1. In sql, there are two ways to express unequal, one is "" (without quotation marks), the other is "! =" (without quotation marks), the usage is the same.

2. That's where a 100; or where a! = 100

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Structured query language (Structured Query Language) referred to as SQL, is a special purpose programming language, is a database query and programming language, used to access data and query, update and manage relational database systems.

Structured query language is a high-level non-procedural programming language that allows users to work on high-level data structures. It does not require the user to specify the data storage method, nor does it require the user to know the specific data storage method, so different database systems with completely different underlying structures can use the same structured query language as the interface for data input and management. Structured query language statements can be nested, which makes it have great flexibility and powerful functions.

The SQL language was proposed by Boyce and Chamberlin in 1974 and was first implemented on the relational database system SystemR developed by IBM Company. Because of its outstanding advantages such as rich functions, convenient and flexible use, concise and easy to learn language, it is deeply welcomed by the computer industry and computer users. In October 1980, X3H2, the database committee of the American National Standards Institute (ANSI), approved SQL as the American standard for relational database language, and published the standard SQL in the same year. Shortly after that, the International Organization for Standardization (ISO) made the same decision.

Functionally, SQL can be divided into three parts: data definition, data manipulation and data control.

The core part of SQL is equivalent to relational algebra, but it has many characteristics that relational algebra does not have, such as aggregation, database update and so on. It is a comprehensive, universal and highly functional relational database language. Its characteristics are as follows:

1. Data description, manipulation, control and other functions are integrated.

2. Two ways of use and unified grammatical structure. SQL can be used in two ways. One is online interactive use, in which SQL is actually used as a self-contained language. Another way is to embed it into a high-level programming language (such as C, etc.). The former method is suitable for non-computer professionals, and the latter is suitable for computer professionals. Although it is not used in the right way, the grammatical structure of the language is basically the same.

3. Highly non-procedural. SQL is a fourth generation language (4GL), users only need to put forward "what to do", do not need to specify "how to do", such as access path selection and specific processing operations are automatically completed by the system.

4. The language is concise and easy to learn and use. Although SQL is very powerful, the language is very concise, and only nine verbs are used in the core function. The grammar of SQL is close to spoken English, so it is easy for users to learn and use it.

The above is all the content of the article "what is the way to express unequal in sql". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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