How to query the field types of mysql database table?

In the mysql database, you can query the field types of the data table through the DESCRIBE statement; this statement can display the field information of the table in the form of a table, including the field name, field data type, whether it is the primary key, and whether There are default values, etc.; the syntax structure is "DESCRIBE table name", which can be abbreviated as "DESC table name".

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DESCRIBE: In the form of a table Display table structure

DESCRIBE/DESC statement will display the field information of the table in the form of a table, including field name, field data type, whether it is the primary key, and whether there is a default value etc.

The syntax format is as follows:

DESCRIBE <表名>;

or abbreviated as:

DESC <表名>;

[Example 1] Use DESCRIBE and DESC respectively to view the table structure and SQL statement of table tb_emp1 And the running results are as follows:

mysql> DESCRIBE tb_emp1;
+--------+-------------+------+-----+---------+-------+
| Field  | Type        | Null | Key | Default | Extra |
+--------+-------------+------+-----+---------+-------+
| id     | int(11)     | YES  |     | NULL    |       |
| name   | varchar(25) | YES  |     | NULL    |       |
| deptId | int(11)     | YES  |     | NULL    |       |
| salary | float       | YES  |     | NULL    |       |
+--------+-------------+------+-----+---------+-------+
4 rows in set (0.14 sec)

mysql> DESC tb_emp1;
+--------+-------------+------+-----+---------+-------+
| Field  | Type        | Null | Key | Default | Extra |
+--------+-------------+------+-----+---------+-------+
| id     | int(11)     | YES  |     | NULL    |       |
| name   | varchar(25) | YES  |     | NULL    |       |
| deptId | int(11)     | YES  |     | NULL    |       |
| salary | float       | YES  |     | NULL    |       |
+--------+-------------+------+-----+---------+-------+
4 rows in set (0.14 sec)

The meaning of each field is as follows:

• Null: Indicates whether the column can store NULL values.

• Key: Indicates whether the column is indexed. PRI means that the column is part of the table's primary key, UNI means that the column is part of a UNIQUE index, and MUL means that a given value is allowed to occur multiple times in the column.

• Default: Indicates whether the column has a default value, and if so, what is the value.

• Extra: Indicates additional information related to a given column that can be obtained, such as AUTO_INCREMENT, etc.

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