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
MODIFY
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>Copy after loginAmong 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)Copy after loginAfter 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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