code: function () {
              var cond = argsToArray(arguments).map(function (s) {
                  return isString(s) && s !== '' ? this.stringToIdentifier(s) : s;
              }, this);
              return this._filter.apply(this, ["having"].concat(cond));
          }
docs: Returns a copy of the dataset with the HAVING conditions changed. See {@link patio.Dataset#filter} for argument types.
  
  @example
  DB.from("items").group("sum").having({sum : 10}).sql;
  //=> SELECT * FROM items GROUP BY sum HAVING (sum = 10)
  
  @return {patio.Dataset} a cloned dataset with HAVING clause changed or added.