rails 検索機能を実装したいのですが、検索後にエラーが出てしまいます

railsで2つのモデルから検索機能を使って表示させようと思い、Userモデル、完全一致でMH（name）と検索すると下記エラーが出てしまいます。これは入力したMHが認識されていないということでしょうか。
どなたかアドバイス頂けると助かります。

ActiveRecord::StatementInvalid in Searches#search
Showing /home/vagrant/work/bookers-app_5/app/views/searches/search.html.erb where line #19 raised:

SQLite3::SQLException: no such column: MH: SELECT "users".* FROM "users" WHERE (MH)
Extracted source (around line #19):
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  	<tbody>
  	  <% @user.each do |user| %>
  	  <tr>
  	  	<td>
  	  	  <%= attachment_imege_tag(user, :profile_image, :fill, 50, 50, fallback: "no-image-mini.jpg") %>

フォームタグ

 <!--検索フォーム -->
      <% if user_signed_in? %>

       <%= form_tag(search_path, method: :get) do %>

        <%=text_field_tag 'word' %>

        <%= select_tag 'range', options_for_select([['---選択してください---',''], ['User', '1'], ['Book', '2']]) %>

        <%= select_tag 'search', options_for_select([['前方一致', 'forword_match'], ['後方一致', 'backword_match'],['完全一致', 'perfect_match'], ['部分一致', 'partial_match']]) %>

        <%= submit_tag '検索' %>

       <% end %>

      <% end %>

　　   <!--検索フォーム -->

searches controller

class SearchesController < ApplicationController
	def search
		@range = params[:range]
		search = params[:search]
		word = params[:word]

		if @range == '1'
			@user = User.search(params[:search],params[:word])
		else
		   @book = Book.search(search,word)
		end
	end
end

user.rb

def self.search(search,word)
      if search == "forword_match"
           User.where(["name LIKE?", "#{word}%"])
      elsif search == "backword_match"
           User.where(["name LIKE?", "%#{word}"])
      elsif search == "perfect_match"
           User.where(["#{word}"])
      elsif search == "partial_match"
           User.where(["name LIKE?", "%#{word}%"])
      else
           User.all
      end
  end

book.rb

def self.search(search,word)
    	if search == 'forword_match'
    		 @book = Book.where('title LIKE?', '#{word}%')
        elsif search == 'backword_match'
        	 @book = Book.where('title LIKE?', '%#{word}')
        elsif search == 'perfect_match'
        	 @book = Book.where('#{word}')
        elsif search == 'partial_match'
        	 @book = Book.where('title LIKE?','%#{word}%')
        else
             @book = Book.all
        end
    end

search.html.erb

 <% if @range == '1' %>
      <h2>Users search for #{word}</h2>

      <table class="table">

      	<thead>
      	  <tr>
      	  	<th>image</th>
      	  	<th>name</th>
      	  </tr>
      	</thead>

      	<tbody>
      	  <% @user.each do |user| %>
      	  <tr>
      	  	<td>
      	  	  <%= attachment_imege_tag(user, :profile_image, :fill, 50, 50, fallback: "no-image-mini.jpg") %>
      	    </td>
      	    <td><%= user.name %></td>
      	    <td><%= link_to 'show', user_path(user) %></td>
      	  </tr>
      	  <% end %>
      	</tbody>

      </table>

      <% else %>

       <h2>Books search for #{word}</h2>

       <table class="table">

      	<thead>
      	  <tr>
      	  	<th>image</th>
      	  	<th>name</th>
      	  </tr>
      	</thead>

      	 <tbody>
      	  <% @book.each do |book| %>
      	  <tr>
      	  	<td>
      	  	  <%= attachment_imege_tag(book.user, :profile_image, :fill, 50, 50, fallback: "no-image-mini.jpg") %>
      	    </td>
      	    <td><%= book.user.name %></td>
      	    <td><%= link_to 'show', user_path(book.user) %></td>
      	  </tr>
      	  <% end %>
      	</tbody>

       </table>

       <% end %>