32-bit and 64-bit integer ranges in PHP and MySQL

Source: Internet
Author: User
Tags echo date php and mysql ranges
A byte has 8 bits, so the 32-bit int takes 32 bits/8 bits = 4 bytes, and the 64-bit int takes 64 bits/8 bits = 8 bytes.

32-bit, 64-bit unsigned integer maximum value:

2^64-1 = 18446744073709551615

2^32-1 = 4294967295

32-bit, 64-bit signed integer maximum value:

(2^32)/2-1 = 2147483647

(2^64)/2-1 = 9223372036854775807

Minus 1 because the integral type includes 0.

The value of 64-bit Ubuntu 14.04,php_int_max is 9223372036854775807, the same as the maximum value of the signed bigint type in MySQL.

The value of 32-bit Ubuntu 14.04,php_int_max is 2147483647, the same as the maximum value of the signed INT in MySQL.

echo Date (' y-m-d h:i:s ', Php_int_max); return 2038-01-19 11:14:07

echo strtotime (' 2038-01-19 11:14:07 '); Returns 2147483647

echo strtotime (' 2038-01-19 11:14:08 '); Returns null under 32 bits

That is, PHP's time () on a 32-bit system can only return a timestamp of 2038-01-19 11:14:07.

Field type: ' Posted ' int (ten) unsigned not NULL DEFAULT ' 0 '

On 32-bit MySQL (same as 64-bit MySQL), an error occurs when inserting a larger number than the 32-bit unsigned int type maximum 2^32-1 = 4294967295:

UPDATE ' PunBB '. ' pb_topics ' SET ' posted ' = ' 4294967296 ' WHERE ' pb_topics '. ' id ' = 1;

Warning: #1264 out of range value for column ' posted ' at row 1

However, MySQL can store 64-bit integers with a 8-byte bigint type.

This article permanently updates the link address : http://www.linuxidc.com/Linux/2016-02/128479.htm

  • Contact Us

    The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

    If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

    A Free Trial That Lets You Build Big!

    Start building with 50+ products and up to 12 months usage for Elastic Compute Service

    • Sales Support

      1 on 1 presale consultation

    • After-Sales Support

      24/7 Technical Support 6 Free Tickets per Quarter Faster Response

    • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.