Special commands in MySql database query

First: Installation of MySQL

Download the MySQL software and modify the installation path

Install the MySQL database 5.7.18

Step 1: Database MySQL5.7.18 can be downloaded from the official website, download address: http://www.filehorse.com/download-mysql-64/,

Step 2: Unzip the downloaded installation package to a disk.

Step 3: Configure environment variables, create a new environment variable MySQL_HOME, and enter the MySQL installation directory.

Then insert ;%MYSQL_HOME%\bin to the end of Path;

Step 4: Run the command line as an administrator, press win+R, enter cmd, right-click and run as an administrator.

Step 5: Switch to the MySQL installation directory and install it using mysqld:

Initialize data: mysqld --initialize-insecure --user=mysql,

Start the service: mysqld --user=mysql,

Initialize mysql root password mysqladmin -u root password 'new-password',

See https://dev.mysql.com/doc/refman/5.7/en/data-directory-initialization-mysqld.html for details.

Step 6: Register service mysqld --install MySQL

Start the service with the net start mysql command.

Enter the mysql -u root -p command: Then fill in the password entered when initializing the database in step 5, as shown below:

Enter show databases; in the mysql command to view the tables in the database, as shown in the following figure:

This indicates that the database has been installed successfully.

Second: Database special query statement

Sort in descending order, select name from data order by name desc; ---- here desc means sort in descending order

Query based on relative column position, select name, price from data order by 2,3; ----- 2,3 means sorting by the second column first, then by the third column.

Note: If you want to sort in descending order on multiple columns, you must specify each column with desc.

third:

The difference between creating a new link and creating a new database in Navicat database software

Creating a new link is to create a data link object, which contains the database

To create a data link,

Select the type of database link to create. Mine is MySQL, set the link name, password and port number.

Electronic MySQL create database

This will create the database.

Summarize

The above are the special commands in MySql database query that I introduced to you. I hope it will be helpful to you. If you have any questions, please leave me a message and I will reply to you in time. I would also like to thank everyone for their support of the 123WORDPRESS.COM website!