Logical Operators, || or OR?

The difference between respectively || and OR and && and AND is operator precedence :

$bool = FALSE || TRUE;

• interpreted as ($bool = (FALSE || TRUE))
• value of $bool is TRUE

---

$bool = FALSE OR TRUE;

• interpreted as (($bool = FALSE) OR TRUE)
• value of $bool is FALSE

---

$bool = TRUE && FALSE;

• interpreted as ($bool = (TRUE && FALSE))
• value of $bool is FALSE

---

$bool = TRUE AND FALSE;

• interpreted as (($bool = TRUE) AND FALSE)
• value of $bool is TRUE

They are used for different purposes and in fact have different operator precedences. The && and || operators are intended for Boolean conditions, whereas and and or are intended for control flow.

For example, the following is a Boolean condition:

if ($foo == $bar && $baz != $quxx) {

This differs from control flow:

doSomething() or die();

There is no "better" but the more common one is ||. They have different precedence and || would work like one would expect normally.

See also: Logical operators (the following example is taken from there):

// The result of the expression (false || true) is assigned to $e
// Acts like: ($e = (false || true))
$e = false || true;

// The constant false is assigned to $f and then true is ignored
// Acts like: (($f = false) or true)
$f = false or true;