SQL statements add fields, modify fields, modify types, and modify default values

Change the default value of a field

Alter table name DROP constraint name ——

Alter table name add constraint name DEFAULT DEFAULT value for column name ——-

Alter table name alter table name

Alter table RENAME column A to B

Alter table type;

Alter TABLE table name ALTER column UnitPrice Decimal (18, 4) not NULL

Alter table add value;

Alter TABLE Table name ADD Field type NOT NULL Default 0