How to find count in many to many relationship in MySql, Cakephp 3.6

Question

I need to calculate the count(vendors.id) for each category. ie: how many vendors are there for each category(not sub-category)

I am using cakephp 3.6 framework and MySQL as database

I tried with all possible way that i knew but not found any solution. Can anybody help me, is very important for my project

[UPDATE] sql query i have used:

SELECT cat.id,cat.name ,COUNT(`vendor_id`) AS vendor_count FROM `vendor_services` JOIN `categories` ON(`vendor_services`.`category_id` = `categories`.`id`) JOIN `categories` AS cat ON(categories.category_id = cat.id) WHERE 1 GROUP BY cat.id

[UPDATE]Bellow is the sql to create corresponding tables

-- phpMyAdmin SQL Dump
-- version 4.7.0
-- https://www.phpmyadmin.net/
--
-- Host: 127.0.0.1
-- Generation Time: Dec 04, 2018 at 10:50 AM
-- Server version: 10.1.24-MariaDB
-- PHP Version: 7.1.6

SET SQL_MODE = "NO_AUTO_VALUE_ON_ZERO";
SET AUTOCOMMIT = 0;
START TRANSACTION;
SET time_zone = "+00:00";

--
-- Database: `demo123`
--

-- --------------------------------------------------------

--
-- Table structure for table `categories`
--

CREATE TABLE `categories` (
  `id` int(11) NOT NULL,
  `category_id` tinyint(4) NOT NULL,
  `name` varchar(60) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

--
-- Dumping data for table `categories`
--

INSERT INTO `categories` (`id`, `category_id`, `name`) VALUES
(1, 0, 'Books'),
(2, 0, 'Electronics'),
(3, 0, 'Garden'),
(4, 1, 'Novel'),
(5, 1, 'Science'),
(6, 1, 'Story'),
(7, 2, 'Mobile'),
(8, 2, 'Tablet'),
(9, 2, 'Headphone'),
(10, 3, 'Pumps'),
(11, 3, 'Pipes');

-- --------------------------------------------------------

--
-- Table structure for table `vendors`
--

CREATE TABLE `vendors` (
  `id` int(11) NOT NULL,
  `name` varchar(60) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

--
-- Dumping data for table `vendors`
--

INSERT INTO `vendors` (`id`, `name`) VALUES
(1, 'VR Enterprizes'),
(2, 'RR Vendors'),
(3, 'JK Suppliers');

-- --------------------------------------------------------

--
-- Table structure for table `vendor_services`
--

CREATE TABLE `vendor_services` (
  `id` int(11) NOT NULL,
  `vendor_id` int(11) NOT NULL,
  `category_id` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

--
-- Dumping data for table `vendor_services`
--

INSERT INTO `vendor_services` (`id`, `vendor_id`, `category_id`) VALUES
(1, 1, 4),
(2, 1, 5),
(3, 1, 6),
(4, 1, 11),
(5, 2, 7),
(6, 2, 8),
(7, 2, 9),
(8, 3, 10),
(9, 3, 11);

--
-- Indexes for dumped tables
--

--
-- Indexes for table `categories`
--
ALTER TABLE `categories`
  ADD PRIMARY KEY (`id`),
  ADD KEY `category_id` (`category_id`);

--
-- Indexes for table `vendors`
--
ALTER TABLE `vendors`
  ADD PRIMARY KEY (`id`);

--
-- Indexes for table `vendor_services`
--
ALTER TABLE `vendor_services`
  ADD PRIMARY KEY (`id`),
  ADD KEY `vendor_id` (`vendor_id`),
  ADD KEY `category_id` (`category_id`);

--
-- AUTO_INCREMENT for dumped tables
--

--
-- AUTO_INCREMENT for table `categories`
--
ALTER TABLE `categories`
  MODIFY `id` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=12;
--
-- AUTO_INCREMENT for table `vendors`
--
ALTER TABLE `vendors`
  MODIFY `id` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=4;
--
-- AUTO_INCREMENT for table `vendor_services`
--
ALTER TABLE `vendor_services`
  MODIFY `id` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=10;COMMIT;

CategoriesTable

$this->hasMany(‘Subcategories’, [ 'className'=> ‘Categories’,
            'foreignKey' => 'category_id',
            'conditions' => ['category_id!= 0']
        ]);

$this->belongsTo('MainCategories', [
                'className'=> ‘Categories’,
                    'foreignKey' => 'category_id',
        ]);

Answer 1

Below is the query in oracle, please have a look, and modify it as per mysql,

added below insertion, INSERT INTO VENDOR_SERVICES (ID, VENDOR_ID, CATEGORY_ID) VALUES(11, 3, 3);

SELECT FRM.CATEGORY_ID, FRM.VENDOR_ID, FRM.VENDER_NAME,COUNT(VENDOR_ID) counts FROM ( SELECT distinct CT.CATEGORY_ID, VS.VENDOR_ID, VS.CATEGORY_ID VS_CATEGORY_ID,vn.ID, vn.NAME VENDER_NAME FROM CATEGORIES CT INNER JOIN VENDOR_SERVICES VS ON VS.CATEGORY_ID=CT.CATEGORY_ID INNER JOIN VENDORS VN ON VS.VENDOR_ID=VN.ID) frm group by CATEGORY_ID, VENDOR_ID, VENDER_NAME