問題描述

我想知道 BigInt、MediumInt 和 Int 之間的區別...更大的數字；但是，我可以制作一個 Int(20) 或一個 BigInt(20) 并且看起來它不一定與大小有關.

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.

一些見解會很棒，只是有點好奇.我一直在使用 MySQL 一段時間，并在選擇類型時嘗試應用業務需求，但我從未理解這方面.

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.

推薦答案

參見 http://dev.mysql.com/doc/refman/8.0/en/numeric-types.html

• INT 是一個四字節的有符號整數.

• INT is a four-byte signed integer.

BIGINT 是一個八字節的有符號整數.

BIGINT is an eight-byte signed integer.

它們每個接受的值都不能多于可以存儲在各自字節數中的值.這意味著 INT 中有 2³² 個值，BIGINT 中有 2⁶⁴ 個值.

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.

INT(20) 和 BIGINT(20) 中的 20 幾乎沒有任何意義.這是顯示寬度的提示.它與存儲無關，也與列將接受的值范圍無關.

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.

實際上，它只影響 ZEROFILL 選項:

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 |
+----------------------+

對于 MySQL 用戶來說，看到 INT(20) 并假設它是一個大小限制，類似于 CHAR(20)，這是一個常見的混淆源.事實并非如此.

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.

這篇關于MySQL 中的類型:BigInt(20) 與 Int(20)的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！