title: How to use "Like" operator in sqlAlchemy
body: <p>Hi I am a new member in stackoverflow. I am currently using sqlAlchemy in flask. Trying to get the matched categories of string provided with the search url. The code of search url is given below:</p>
  
  <pre><code>@productapi.route("/search/category", methods=["GET"])
  def search_category():
      category_param_value = request.args.get('querystr', None)
      print(category_param_value)
      if category_param_value is None:
          return jsonify(message='Which category you want to search????'), 400
      try:
          category = Category.query.filter_by(
              title=Category.title.like("category_param_value %"))
      except SQLAlchemyError as err:
          return jsonify(message='Category not found.'), 400
      category_list = category_schema.dumps(category)
      return category_list.data, 200
  </code></pre>
  
  <p>I tried with httpie with following url: http get <a href="http://192.168.1.98:5000/api/v1/search/category?querystr=" rel="noreferrer">http://192.168.1.98:5000/api/v1/search/category?querystr=</a>"test"</p>
  
  <p>Error: </p>
  
  <pre><code>sqlalchemy.exc.ProgrammingError: (psycopg2.ProgrammingError) operator does not exist: character varying = boolean
  </code></pre>
  
  <p>Hoping for a positive response. Thank You.</p>