How can i rotate the camera with the mouse but only when drag ?

The code was working fine but now i want that i will be able to rotate the camera only when pressing down the left mouse button. So i added this if:

 if (Input.GetMouseButton(0))

But it's still make the character moving since it's also a click. I don't want the character to move. When pressing the mouse button down i want it only to rotate and if i make a click without pressing down then move the character.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class MouseOrbit : MonoBehaviour {
 
     public Transform target;
     public float distance = 5.0f;
     public float xSpeed = 120.0f;
     public float ySpeed = 120.0f;
 
     public float yMinLimit = -20f;
     public float yMaxLimit = 80f;
 
     public float distanceMin = .5f;
     public float distanceMax = 15f;
 
     private Rigidbody rigidbody;
 
     float x = 0.0f;
     float y = 0.0f;
 
     // Use this for initialization
     void Start()
     {
         Vector3 angles = transform.eulerAngles;
         x = angles.y;
         y = angles.x;
 
         rigidbody = GetComponent<Rigidbody>();
 
         // Make the rigid body not change rotation
         if (rigidbody != null)
         {
             rigidbody.freezeRotation = true;
         }
     }
 
     void Update()
     {
         // Updating camera distance on every frame
         distance = RayCast3.distance3;
 
         //Setting maximum distance so the camera doesnt go too far
         if (distance > 2)
         {
             distance = 2;
         }
     }
 
     void LateUpdate()
     {
         if (target)
         {
             if (Input.GetMouseButton(0))
             {
                 x += Input.GetAxis("Mouse X") * xSpeed * distance * 0.02f;
                 y -= Input.GetAxis("Mouse Y") * ySpeed * 0.02f;
             }
                 y = ClampAngle(y, yMinLimit, yMaxLimit);
 
                 Quaternion rotation = Quaternion.Euler(y, x, 0);
 
                 RaycastHit hit;
                 if (Physics.Linecast(target.position, transform.position, out hit))
                 {
                     distance -= hit.distance;
                 }
                 Vector3 negDistance = new Vector3(0.0f, 0.0f, -distance);
                 Vector3 position = rotation * negDistance + target.position;
 
                 transform.rotation = rotation;
                 transform.position = position;
         }
     }
 
     public static float ClampAngle(float angle, float min, float max)
     {
         if (angle < -360F)
             angle += 360F;
         if (angle >= 360F)
             angle -= 360F;
         return Mathf.Clamp(angle, min, max);
     }
 }