and和or的优先级比&&和||高 .更确切地说，&&和||的优先级高于赋值运算符(=)，而and和or的优先级更低.

and and or have higher lower precedence than && and ||. To be more exact && and || have higher precedence than assignment operator ( = ) while and and or have lower.

http://www.php.net/manual/zh/language.operators.precedence.php

通常它没有什么区别，但是在某些情况下，不知道这种区别会导致某些意外行为.在此处查看示例:

Usually it doesn't make a difference, but there are cases when not knowing about this difference can cause some unexpected behaviour. See examples here:

http://php.net/manual/en/language.operators. logical.php