How to view a table in MySQL

MySQL is an open source relational database management system that is often used to build Web applications. When using MySQL, you often need to view and manage tables. So, this article will introduce how to view tables in MySQL and help readers better master the use of MySQL.

1. Use the SHOW command

The SHOW command is a command in MySQL used to display the tables and views under the current database. The format is as follows:

SHOW [FULL] TABLES [FROM db_name] [LIKE 'pattern']

Among them, the db_name parameter is the database name and must be filled in. If not filled in, the SHOW command will display which tables are included in the currently used database; the pattern parameter is a pattern string, which can be used to match table names or view names to filter the displayed content. The output of the above command includes two columns: Tables in [db_name] and Table_type. Among them, the Tables in [db_name] column displays the table names contained in the database, and the Table_type column displays the type of table (basically BASE TABLE).

If you want to view the specific structure of a table, you can use the following command:

SHOW COLUMNS FROM table_name [FROM db_name]

Among them, table_name is the name of the table whose structure needs to be viewed, and db_name is the name of the database. After executing the above command, MySQL will display detailed information about each column of the table, including column name, column type, whether null is allowed, default value, etc. Through this command, we can clearly understand the field information and characteristics of the table.

If you want to view the detailed information and status values ​​of the MySQL server parameters, you can use the following command:

SHOW VARIABLES [LIKE 'pattern']

2. Use the DESCRIBE command

The DESCRIBE command can be used to view the table detailed structure. The format of the execution command is as follows:

DESCRIBE table_name

Among them, table_name indicates the name of the table to be viewed. After executing this command, MySQL will display detailed information about each column of the table, including column name, data type, whether null is allowed, default value, etc. Similar to the SHOW COLUMNS command, the DESCRIBE command can also be used to view field information of a MySQL table. The difference is that the results output by the DESCRIBE command only include the field name, type and information about whether null is allowed, and the DESCRIBE command cannot add a LIKE clause.

3. Use INFORMATION_SCHEMA

INFORMATION_SCHEMA is a metadata information database in MySQL. It contains a large amount of metadata information about databases, tables, columns, indexes, etc. Users can use INFORMATION_SCHEMA to obtain this metadata information to achieve certain goals.

The following are some commonly used INFORMATION_SCHEMA queries:

SELECT table_name FROM information_schema.tables WHERE table_schema = 'database_name';

Among them, database_name is the name of the database that needs to be viewed.

With this command, we can query all table names contained in the database.

If you need to view the column information of the table, you can use the following command:

SELECT column_name, data_type, is_nullable, column_default FROM information_schema.columns WHERE table_schema = 'database_name' AND table_name = 'table_name';

Among them, table_name represents the name of the table that needs to be viewed, and database_name represents the name of the database to which the table belongs. This command can display detailed information about each column in the table, including column name, data type, whether null is allowed, default value, etc.

Summary

There are many ways to view tables in MySQL, such as using the SHOW command, DESCRIBE command and INFORMATION_SCHEMA. Each method has its own unique advantages, disadvantages and applicable situations. When using it, we need to choose the most appropriate method to view and manage the table according to the actual situation. In addition, we can also use MySQL graphical tools to view and manage tables, which requires the help of third-party software, such as MySQL Workbench.

In short, MySQL is a very powerful database system that can provide excellent performance and reliable security. Understanding how to view and manage MySQL tables is very important to improve the efficiency and ability of using MySQL. At the same time, correctly managing and maintaining MySQL tables can also effectively ensure the stability and reliability of the MySQL database.

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