Условия

// Тернарный оператор

$a = ($b>5 ? $x : $y);

// С фигурными скобками

if ($a > $b) {
    echo "a is bigger than b";
}
else if ($a == $b) {
    echo "a is equal to b";
}
else {
    echo "a is smaller than b";
}

// В стиле Python

if ($a > $b):
    echo $a." is greater than ".$b;
elseif ($a == $b):
    echo $a." equals ".$b;
else:
    echo $a." is neither greater or equal to ".$b;
endif;

// Оператор switch

switch ($i) {
case 0:
case 1:
    echo "i equals 0 or 1";
    break;
case 2:
    echo "i equals 2";
    break;
default:
    echo "i equals 3";
}