class Formula

class Formula extends ArgumentPluginBase {
    public $formula = NULL;
    
    /**
     * {@inheritdoc}
     */
    public function init(ViewExecutable $view, DisplayPluginBase $display, array &$options = NULL) {
        parent::init($view, $display, $options);
        if (!empty($this->definition['formula'])) {
            $this->formula = $this->definition['formula'];
        }
    }
    public function getFormula() {
        return str_replace('***table***', $this->tableAlias, $this->formula);
    }
    
    /**
     * Build the summary query based on a formula.
     */
    protected function summaryQuery() {
        $this->ensureMyTable();
        // Now that our table is secure, get our formula.
        $formula = $this->getFormula();
        // Add the field.
        $this->base_alias = $this->name_alias = $this->query
            ->addField(NULL, $formula, $this->field);
        $this->query
            ->setCountField(NULL, $formula, $this->field);
        return $this->summaryBasics(FALSE);
    }
    
    /**
     * Build the query based upon the formula.
     */
    public function query($group_by = FALSE) {
        $this->ensureMyTable();
        // Now that our table is secure, get our formula.
        $placeholder = $this->placeholder();
        $formula = $this->getFormula() . ' = ' . $placeholder;
        $placeholders = [
            $placeholder => $this->argument,
        ];
        $this->query
            ->addWhere(0, $formula, $placeholders, 'formula');
    }

}