/** * Prepare the queries used for the pre processing * * @return self */ protected function prepareQueries() { $this->xAxisQuery = clone $this->baseQuery; $this->xAxisQuery->distinct(); $this->xAxisQuery->setColumns(array($this->xAxisColumn)); $this->yAxisQuery = clone $this->baseQuery; $this->yAxisQuery->distinct(); $this->yAxisQuery->setColumns(array($this->yAxisColumn)); return $this; }