mysql 类型 bigint,MySQL中的类型：BigInt（20）与Int（20）

最新推荐文章于 2025-08-19 19:13:53 发布

转载最新推荐文章于 2025-08-19 19:13:53 发布 · 752 阅读

文章标签：

#mysql 类型 bigint

本文解释了MySQL中INT、BIGINT等整数类型的差异，并澄清了INT(20)等表示方式的误解，实际它仅影响显示宽度而非存储大小。

I was wondering what the difference between BigInt, MediumInt, and Int are... it would seem obvious that they would allow for larger numbers; however, I can make an Int(20) or a BigInt(20) and that would make seem that it is not necessarily about size.

Some insight would be awesome, just kind of curious. I have been using MySQL for a while and trying to apply business needs when choosing types, but I never understood this aspect.

解决方案INT is a four-byte signed integer.

BIGINT is an eight-byte signed integer.

They each accept no more and no fewer values than can be stored in their respective number of bytes. That means 232 values in an INT and 264 values in a BIGINT.

The 20 in INT(20) and BIGINT(20) means almost nothing. It's a hint for display width. It has nothing to do with storage, nor the range of values that column will accept.

Practically, it affects only the ZEROFILL option:

CREATE TABLE foo ( bar INT(20) ZEROFILL );

INSERT INTO foo (bar) VALUES (1234);

SELECT bar from foo;

+----------------------+

| bar |

+----------------------+

| 00000000000000001234 |

+----------------------+

It's a common source of confusion for MySQL users to see INT(20) and assume it's a size limit, something analogous to CHAR(20). This is not the case.