Add columns to MySQL table at the specified location

ALTER TABLE test ADD COLUMN ID INT UNSIGNED not NULL auto_increment PRIMARY KEY First

Adding columns to a table is a common operation, and when MySQL adds columns, you can specify the location of the column
Adding a column to a specified location requires two keywords:
FirstAnd After
FirstIndicates that the column is incremented first
After indicates an increase after a column
Note that MySQL does not use before when adding columns to the specified position, and the first column can be used First, non-first column usesAfter .
Syntax:

ALTER TABLE table_name ADD [COLUMN] col_name column_definition  [First | After Col_name]

Instance:

DROP TABLE IF EXISTS ' test '; CREATE TABLE ' test ' (  ' a ' int (one) ' is not null,  ' B ' varchar ($) NOT null) Engine=innodb DEFAULT Charset=utf8;

Add a column C after the test table a column:

ALTER TABLE Test ADD COLUMN C INT not NULL after a

Increase the field ID in the first column of the test table:

ALTER TABLE test ADD COLUMN ID INT UNSIGNED not NULL auto_increment PRIMARY KEY First

Complete the full text.

Add columns to MySQL table at the specified location