0 value integer does not enter If

I'm sure this is a very basic coding mistake...

I'm picking up a reading from A0. If the value is 0, I want the value of the serial to be written to the Serial Monitor.

I also want it only to write to the Serial Monitor for the first time that the value falls to 0.

I don't understand why, when the value for SensorValue = 0, the if is not performed.

This is my code:

boolean must_print = true;
int sensorValue = 0;

// the setup routine runs once when you press reset:
void setup() {
// initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
}

// the loop routine runs over and over again forever:
void loop() {
  // read the input on analog pin 0:
  sensorValue = analogRead(A0);

  if (sensorValue = 0) {

     if (must_print = true)
    {
     must_print = false;
     Serial.println(sensorValue);
    }
  else
    must_print = true
  }


   delay(500);        // delay in between reads for stability
}

Thanks!