The if statement in the example above allows to execute a code fragment, when the condition is met. When you want to execute a code fragment, when the condition is not met you extend the if with an else.

if ($a > $b) {
  echo "a is greater than b";
} else {
  echo "a is NOT greater than b";
}

PHP Manual - Control Structures - Else

The ternary operator as shorthand syntax for if-else

The ternary operator evaluates something based on a condition being true or not. It is a comparison operator and often used to express a simple if-else condition in a shorter form. It allows to quickly test a condition and often replaces a multi-line if statement, making your code more compact.

This is the example from above using a ternary expression and variable values: $a=1; $b=2;

echo ($a > $b) ? "a is greater than b" : "a is NOT greater than b";

Outputs: a is NOT greater than b.