zerofill位数填充
mysql> create table shop( -> article int(4) unsigned zerofill default ‘0000‘ not null, -> dealer char(20) default ‘‘ not null, -> price double(16,2) default ‘0.00‘ not null, -> primary key(article,dealer)); mysql> insert into shop values(1,‘A‘,3.45),(1,‘B‘,3.99),(2,‘A‘,10.99),(3,‘B‘,1.4 5),(3,‘C‘,1.69),(3,‘D‘,1.25),(4,‘D‘,19.95); Query OK, 7 rows affected (0.01 sec) Records: 7 Duplicates: 0 Warnings: 0 mysql> select * from shop; +---------+--------+-------+ | article | dealer | price | +---------+--------+-------+ | 0001 | A | 3.45 | | 0001 | B | 3.99 | | 0002 | A | 10.99 |