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Editor to share with you how to use Mysql commands to achieve hierarchical search for help, I believe that most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to know it!

Query all help

If we want to know what kind of help mysql can give us, we can use the following command

? Contents

Or will? It can also be replaced with help, and the two effects are the same.

Help contents

The effect is as follows

? Equivalent to help in order to make it easy to use?, but readers need to know that if we use help, it will have the same effect.

Various explanations

English and Chinese instructions

Account Management account management

Administration management

Compound Statements compound statement

Data Definition data definition

Data Manipulation data operation

Data Types data type

The Functions function is usually a non-sql standard original command provided only by this product and the same series of products.

Functions and Modifiers for Use with GROUP BY grouping functions and decorations

Geographic Features distributed feature

Help Metadata metadata

Language Structure language structure

Plugins plug-in

Procedures stored procedure

Storage Engines storage engine

Table Maintenance table maintenance

Transactions transaction

User-Defined Functions user-defined function

Utility other help here I can not specifically understand the Chinese meaning, but suggest readers to implement? Utility, see what help it can provide.

Hierarchical View help

Now that we know what types of help can be found, we can use question marks + spaces + specific names for different projects = = case-insensitive = =

For example, I want to find out which data types are supported

? Data type

The effect is as shown in the picture

There are many data types, usually we may only use char varchar int boolean bit timestamp datetime float, etc., but there are many things we don't know and seldom use, such as BIGINT, ENUM, BLOB, etc., so when we are involved in database optimization, we need to know more about the characteristics of a certain type or want to know whether there is a more suitable data type, so we can all use it? Find the appropriate data type

The figure below is as follows

So now we know that BLOB is a data type that can hold 65535 bytes.

The above is all the contents of how Mysql uses commands to achieve hierarchical search for help. Thank you for your 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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