How to add new fields in MySQL

Adding new fields in MySQL

To add a new field in MySQL, you can use the ALTER TABLE statement.

Here is the basic syntax for adding new fields:

ALTER TABLE table_name ADD column_name datatype;

in:

table_nameis the name of the table in which you want to add a new field.
column_nameis the name of the new field.
datatypeis the data type of the new field. For example,VARCHAR、INTorDOUBLEwait.

Here is an example ALTER TABLE statement that demonstrates how to nameuserAdd a table namednameThe new field of the data type is VARCHAR(10):

ALTER TABLE users ADD phone_number VARCHAR(10);

Note that if you have to place a new column in a specific position in the table, you can use the following syntax:

ALTER TABLE table_name ADD column_name datatype AFTER another_column;

inanother_columnis the name of the column that already exists, and the new column will be placed after the column.

For example, the following command will give the nameuserAdd a table namednamenew column with data typeVARCHAR(10)and place it inidAfter column:

ALTER TABLE user ADD name VARCHAR(10) AFTER id;

Add a new field at the last position of the table (default)

grammar:

    ALTER TABLE Table name
        ADD New field name Data Type Constraints
    ;

Add new fields at the beginning of the table

grammar:

    ALTER TABLE Table name
        ADD New field name Data Type Constraints FIRST
    ;

Add a new field after a field

grammar:

    ALTER TABLE Table name
        ADD New field name Data Type Constraints AFTER Already field names
    ;

MySQL table add fields sql statement

Add fields to tables in MySQL database using ALTER TABLE

Syntax Rules

ALTER TABLE table_name ADD COLUMN column_name VARCHAR(100) DEFAULT NULL COMMENT 'Add a new field' AFTER old_column;

Statement content

table_name: Table name;
column_name: The field name that needs to be added;
VARCHAR(100): The field type is varchar, length 100;
DEFAULT NULL: Default value NULL;
AFTER old_column: Add new fields after the old_column field, and if you don't write them, the default end of the table will be the default;

example:

ALTER TABLE xyd_case_info ADD COLUMN `deleted` TINYINT(1) NULL DEFAULT NULL COMMENT '0, normal, 1 delete';
ALTER TABLE xyd_case_info ADD COLUMN `create_by` VARCHAR(50) NULL DEFAULT NULL COMMENT 'Create person' COLLATE 'utf8mb4_general_ci';
ALTER TABLE xyd_case_info ADD COLUMN `create_time` DATETIME NULL DEFAULT NULL COMMENT 'Create time';
ALTER TABLE xyd_case_info ADD COLUMN `update_by` VARCHAR(50) NULL DEFAULT NULL COMMENT 'Update person' COLLATE 'utf8mb4_general_ci';
ALTER TABLE xyd_case_info ADD COLUMN `update_time` DATETIME NULL DEFAULT NULL COMMENT 'Update time';

Summarize

The above is personal experience. I hope you can give you a reference and I hope you can support me more.