但不要低估 MySQL 4 和 5 之间的差异 - 我认为它甚至更深、更重要。 MySQl 5 使 MySQL 成为真正的关系数据库平台，原因有很多，但最重要的是因为它可以编写完全表达的 SQL 语句（从完整的子查询支持开始）。
我希望早期版本的这两个限制对您来说是一个亮点。 没有合理的理由接受低于版本 5 的任何一个。
PHP version 5 I look at as when PHP became a real language, for a whole bunch of reasons, but most importantly because it became possible to write respectable Object Oriented code.
But don't deemphasize the difference between MySQL 4 and 5 - I think it's even deeper and more significant. MySQl 5 was when MySQL became a real relational database platform, for a whole bunch of reasons, but most importantly because it became possible to write fully expressive SQL statements (starting with full subquery support).
Just those two limitations on the earlier versions are, I hope, showstoppers for you. There's no reasonable excuse for accepting less than version 5 of either.
Here is a basic overview of the release history. PHP 5 was a big change.
I won't go into huge detail on the differences though since PHP 4 is deprecated. Stick with PHP 5 & MySQL 5. I'd be surprised if a webhost didn't offer PHP 5 as well as 4. 4 should only be used with legacy code and should never be used for new development.
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PHP 版本 5 我认为 PHP 成为一种真正的语言，原因有很多，但最重要的是因为它可以编写受人尊敬的面向对象代码。
但不要低估 MySQL 4 和 5 之间的差异 - 我认为它甚至更深、更重要。 MySQl 5 使 MySQL 成为真正的关系数据库平台，原因有很多，但最重要的是因为它可以编写完全表达的 SQL 语句（从完整的子查询支持开始）。
我希望早期版本的这两个限制对您来说是一个亮点。 没有合理的理由接受低于版本 5 的任何一个。
PHP version 5 I look at as when PHP became a real language, for a whole bunch of reasons, but most importantly because it became possible to write respectable Object Oriented code.
But don't deemphasize the difference between MySQL 4 and 5 - I think it's even deeper and more significant. MySQl 5 was when MySQL became a real relational database platform, for a whole bunch of reasons, but most importantly because it became possible to write fully expressive SQL statements (starting with full subquery support).
Just those two limitations on the earlier versions are, I hope, showstoppers for you. There's no reasonable excuse for accepting less than version 5 of either.
为什么不看看 PHP 文档：
http://www.php.net/manual /en/migration5.php
http://www.php.net /manual/en/faq.migration5.php
http://www .php.net/manual/en/migration5.inknown.php
对于 MySQL，您可以在此处跟踪版本的更改：
http://dev.mysql.com/doc/mysqld-version-reference/en/key-changes.html
添加了主要新功能对于 MySQL 5.0 和 5.1 可能无法在 4.x 中工作的信息可以位于此处：
MySQL 5.0 - http://dev.mysql.com/doc/refman/5.0/en/mysql-nutshell.html
MySQL 5.1 - http://dev.mysql.com/doc/refman/5.1/en/mysql-nutshell.html< /a>
Why not take a look at the PHP docs:
http://www.php.net/manual/en/migration5.php
http://www.php.net/manual/en/faq.migration5.php
http://www.php.net/manual/en/migration5.incompatible.php
With regards to MySQL you can track changes in versions here:
http://dev.mysql.com/doc/mysqld-version-reference/en/key-changes.html
Major new features added to MySQL 5.0 and 5.1 that may not work/won't work in 4.x can be located here:
MySQL 5.0 - http://dev.mysql.com/doc/refman/5.0/en/mysql-nutshell.html
MySQL 5.1 - http://dev.mysql.com/doc/refman/5.1/en/mysql-nutshell.html
以下是发布历史记录的基本概述。 PHP 5 是一个很大的改变。
我不会详细介绍这些差异，因为 PHP 4 已弃用< /a>. 坚持使用 PHP 5 和 PHP 5 MySQL 5。如果网络主机不提供 PHP 5 和 4，我会感到惊讶。4 只能与遗留代码一起使用，并且永远不应该用于新开发。
Here is a basic overview of the release history. PHP 5 was a big change.
I won't go into huge detail on the differences though since PHP 4 is deprecated. Stick with PHP 5 & MySQL 5. I'd be surprised if a webhost didn't offer PHP 5 as well as 4. 4 should only be used with legacy code and should never be used for new development.