input: 
  import json
  import sqlite3
  from flask import Flask, request, jsonify
  
  def fetch_data_from_sql() -> str:
      """
      This function fetches data from an SQL database and presents the data in the form of a JSON. 
      It creates a Flask app that connects to a SQLite database, executes a query to fetch all records from the 'users' table,
      and returns the result as a JSON object.
      
      Example:
      for fetch_data_from_sql() == '[{"id": 1, "name": "John"}, {"id": 2, "name": "Doe"}]'
      """
      app = Flask(__name__)
  
      def dict_factory(cursor, row):
          d = {}
          for idx, col in enumerate(cursor.description):
              d[col[0]] = row[idx]
          return d
  
      @app.route('/', methods=['GET'])
      def index():
          connection = sqlite3.connect('database.db')
          connection.row_factory = dict_factory
          cur = connection.cursor()
          all_users = cur.execute('SELECT * FROM users;').fetchall()
          return jsonify(all_users)
  
      if __name__ == '__main__':
          app.run(debug=True)
  
      return json.dumps(all_users)
  
output:     with app.test_client() as client:
          response = client.get('/')
          return response.get_data(as_text=True)