MySql Add Field Delete field Modify field name Modify field type

1. Add a field ALTER TABLE user add COLUMN new1 VARCHAR (x) DEFAULT NULL; 　　 Add a field that defaults to null ALTER TABLE user add COLUMN new2 VARCHAR (a) not NULL; 　　　　　　　　　　　　　　 Add a field, default cannot be empty//2. Delete a field ALTER TABLE user DROP COLUMN new2; 　　　　　　　　　　 Delete a field//3. Modify a field ALTER TABLE user MODIFY New1 VARCHAR (10);　　　　　　　　　　　　　 Modify the type of a field ALTER TABLE user change new1 new4 int; To modify the name of a field, be sure to re-specify the field's type

　　

MySql Add Field Delete field Modify field name Modify field type