Method sum

src/model.js:2235–2237

* Find the sum of field * * @param {string} field attribute / field name * @param {object} [options] See aggregate * * @see * Model.aggregate for options * * @returns {Promise }

(field, options)

   * @returns {Promise<number>}
   */
  static async sum(field, options) {
    return await this.aggregate(field, 'sum', options);
  }

  /**
   * Builds a new model instance.