如何在此if语句中添加“OR”运算符？

Question

我有这个IF语句，我想添加一个OR，所以它应该是if（$ variable1 == $ variable2）或if（$ variable3 == $ variable4）。

if($variable1 == $variable2)
die("");

else
echo("");

Answer 1

if($variable1 == $variable2 || $variable3 == $variable4){
die("");
}
else{
echo("");}

Answer 2

请参阅PHP Logical Operators

 if($variable1 ==$variable2 || $variable3 == $variable4) {
//do whatever
}

Answer 3

if($variable1 == $variable2  || $variable3 == $variable4)
die("");
else
echo("");