Question

MySQL数据类型 int什么意思

Answer 1

int(m)
zerofill，加上zerofill后m才表现出有点点效果，比如
int(3)
zerofill,你插入到数据库里的是10,则实际插入为010,也就是在前面补充加了一个0.如果int(3)和int(10)不加
zerofill,则它们没有什么区别．m不是用来限制int个数的．int(m)的最大值和最小值与undesigned有关，最下面那副图有说明．
mysql>
create
table
t
(t
int(3)
zerofill);
query
ok,
0
rows
affected
(0.00
sec)
mysql>
insert
into
t
set
t
=
10;
query
ok,
1
row
affected
(0.00
sec)
mysql>
select
*
from
t;
+——+
|
t
|
+——+
|
010
|
+——+
1
row
in
set
(0.11
sec)
zerofill
with
default
width,
the
same
as
int(10):
mysql>
create
table
t
(t
int
zerofill);
query
ok,
0
rows
affected
(0.02
sec)
mysql>
insert
into
t
set
t
=
10;
query
ok,
1
row
affected
(0.02
sec)
mysql>
select
*
from
t;
+————+
|
t
|
+————+
|
0000000010
|
+————+
1
row
in
set
(0.08
sec)
without
zerofill:
mysql>
create
table
t
(t
int);
query
ok,
0
rows
affected
(0.01
sec)
mysql>
insert
into
t
set
t
=
10;
query
ok,
1
row
affected
(0.01
sec)
mysql>
select
*
from
t;
+——+
|
t
|
+——+
|
10
|
+——+
1
row
in
set
(0.00
sec)

Answer 2