以0开头的数据库数字字段

Question

I am using a field named as area_code that has int data-type in MySQL. But it doesn't allow me to store exact values like 0781, 0727, 0788 Bcoz they are starting with 0. It stores the values as 781, 727 and 788 ie it truncates 0 from the values and save it.

Please help me..

Answer 1

Area codes are not numbers, but text (which contains digits only). Declare area_code as a varchar field of appropriate size.

Answer 2

drop table if exists foo;
create table foo
(
area_code smallint(4) unsigned zerofill not null default 0
)
engine=innodb;

insert into foo (area_code) values (781),(727);

select * from foo;
+-----------+
| area_code |
+-----------+
|      0781 |
|      0727 |
+-----------+

http://dev.mysql.com/doc/refman/5.0/en/numeric-types.html

Answer 3

使用基于字符的数据类型，而不是数字数据类型。

Answer 4

使用VARCHAR，因为您不需要对区号进行任何算术运算

Answer 5

if you want your result as 4 digits you can maybe do it in this way:

select lpad(area_code, 4, '0') from zipcode_list;

now you can store the 3 numbers in your database and returning the zero before.