How to modify the data type of mysql column?

How to modify the data type of mysql column: Modify it through the "ALTER TABLE" statement with the MODIFY keyword, the syntax "ALTER TABLE ccc43248daffbac9770dee47fdaff697 MODIFY 6b6432543b1e7cb75ed0a61f84e3d256

Modify field (column) data type

Modifying the data type of a field is to convert the data type of the field into another data type. The syntax rules for modifying field data types in MySQL are as follows:

ALTER TABLE <表名> MODIFY <字段名> <数据类型>

Among them:

• Table name: refers to the name of the table where the field whose data type is to be modified is located;

• Field name: refers to the field that needs to be modified;

• Data type: refers to the new data type of the modified field.

Example:

Use ALTER TABLE to modify the structure of table tb_emp1, and change the data type of the name field to VARCHAR(22) into VARCHAR(30), the SQL statement and running results are as follows.

mysql> ALTER TABLE tb_emp1
    -> MODIFY name VARCHAR(30);
Query OK, 0 rows affected (0.15 sec)
Records: 0  Duplicates: 0  Warnings: 0
mysql> DESC tb_emp1;
+--------+-------------+------+-----+---------+-------+
| Field  | Type        | Null | Key | Default | Extra |
+--------+-------------+------+-----+---------+-------+
| col1   | int(11)     | YES  |     | NULL    |       |
| id     | int(11)     | YES  |     | NULL    |       |
| name   | varchar(30) | YES  |     | NULL    |       |
| col2   | int(11)     | YES  |     | NULL    |       |
| deptId | int(11)     | YES  |     | NULL    |       |
| salary | float        | YES  |     | NULL    |       |
+--------+-------------+------+-----+---------+-------+
6 rows in set (0.00 sec)

After the statement is executed, it is found that the data type of the name field in table tb_emp1 has been modified to VARCHAR(30), and the modification is successful.

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