sync without detaching laravel code example

Example 1: whereHas site:https://laravel.com/docs/

use Illuminate\Database\Eloquent\Builder;

// Retrieve posts with at least one comment containing words like code%...
$posts = Post::whereHas('comments', function (Builder $query) {
    $query->where('content', 'like', 'code%');
})->get();

// Retrieve posts with at least ten comments containing words like code%...
$posts = Post::whereHas('comments', function (Builder $query) {
    $query->where('content', 'like', 'code%');
}, '>=', 10)->get();

Example 2: laravel attach

//id for single
$user->reasons->attach($reasonId);

//array for multiple
$user->reasons->attach($reasonIds);

$user->save();

Example 3: laravel has many

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Post extends Model
{
    /**
     * Get the comments for the blog post.
     */
    public function comments()
    {
        return $this->hasMany('App\Models\Comment');
    }
}

Example 4: laravel pivot table model

/*Model - Service*/
public function customer(){
    return $this->belongsToMany('customer')->withPivot(
        'start_date',
        'stop_date',
        'rem_date',
        'due_date',
        'status'
        );
}

/*Model - customer*/
public function services(){
    return $this->belongsToMany('Service')->withPivot(
        'start_date',
        'stop_date',
        'rem_date',
        'due_date',
        'status'
        );
}

////These following relations didnt workout
/*Model - custserv*/ //uses the pivot table customer_service//
public function staff(){
    return $this->belongsToMany('Staff');
}

/*Model - Staff*/
public function custservs(){
    return $this->belongsToMany('Custserv');
}

/*schema for pivot table 'staff' and 'Custserv' */
Schema::create('customer_service_user', function(Blueprint $table)
    {
        $table->increments('id');
        $table->integer('customer_service_id')->unsigned()->index();
        $table->foreign('customer_service_id')->references('id')->on('customer_service')->onDelete('cascade');
        $table->integer('staff_id')->unsigned()->index();
        $table->foreign('staff_id')->references('id')->on('staff')->onDelete('cascade');
        $table->timestamps();
    });