Mysql classic high-level/command line operation (quick) (recommended)

Since I need to learn how to build servers and databases, I have recently started to teach myself the SQL language. As for writing databases, I use the more basic MySQL database. Although MySQL has been eliminated by Internet companies, they are all using NoSQL, SQL server and other SQL languages. In the end, I still decided to start with the basics. After a simple decision, I wrote it using the high-end cmd command line. I won’t give a detailed tutorial on how to install the MySQL database here. There are many installation tutorials on the Internet that you can choose to install on your own.

1. The first step is to create a library in Mysql

Take MySQL 5.0 as an example. After installation, log in to MySQL from the command line:
Enter in the command line: mysql -u root(用戶名) -p

Then enter the password as prompted and log in to the database;

After logging in, enter show databases to view the libraries in the database:

Among them:

information_schema,
Mysql,
Test,
Performance_schema

These three libraries are installed with MySQL, so you don't need to use them. Next, create your own database to use:

Enter create database Cheung, then use the database you created by entering use Cheung;

The appearance of the above interface means that the database we are currently using is Cheung. The preparations are now complete, and we will begin the formal SQL statement practice.

2. Let's learn how to create a table:

Enter the following operations in the command line to create a table in the database. Some operations will add single quotes to the name of each data, but this is not necessary. The effects of the two are the same:

This means that the table tab to be used has been created. We can enter: desc tab

To check whether the table you see is correct

When entering each data, remember to add commas to separate them, otherwise an error will occur in table creation. This is usually very embarrassing, so you must pay more attention to details. Do not add extra brackets between the last bracket and the data, because adding them will result in an error.

3. Update the structure of the table in the database

Update the table definition and add a row to the table using the alter table + table name command:

If you want to delete a column in a table, you need to use the keyword Column. The specific operations are as follows:

If you want to delete the entire table, just enter:

4. Use Insert to insert data

Let's first look at the current structure of the tab table:

To insert data into a table, you need to use the Insert statement in the following format:

Insert into table name (column name 1, column name 2, ...) values ​​(value 1, value 2, ...)

The following shows how to insert a complete set of data:

Please note that I did not set the id value to be self-incrementing in advance, that is, I did not write it when creating the table:

id int not null auto_increment

Therefore, the id column in the table cannot be self-incremented, so you need to write the id item when inserting data, otherwise an error will be reported.

What we need to do next is to insert multiple sets of data into the created table at the same time:

It took a lot of effort to write these operations for the first time, but finally my hard work paid off. After working hard until 3 a.m. in the middle of the night, I finally got the correct answer.

It is relatively easy to query the data in the table, so I won't go into details here.

5. Use the update statement to update a column

The format is: update 表名set 屬性1= 新值1，屬性2 = 新值2 where 屬性3 = ?

The format is not difficult to understand, the key is to use it proficiently.

Finally, delete the table data:

And finally clear the entire table:

In this way, a complete Mysql command line high-end operation is completed. During the learning process, I had no contact with similar database languages, so I directly started with the command line. I stepped on many pitfalls in the process. Here I will also help you to clear the pitfalls. If you have similar problems in the future, it will be easier to solve them. I will continue to learn other sql languages ​​in the future.

The above is a detailed integration of MySQL command line operations introduced by the editor. I hope it will be helpful to everyone. If you have any questions, please leave me a message and the editor will reply to you in time. I would also like to thank everyone for their support of the 123WORDPRESS.COM website!