leftExpression = $leftExpression; $this->rightExpression = $rightExpression; $this->keyword = $keyword; } public function getLeftExp() { return $this->leftExpression; } public function getRightExp() { return $this->rightExpression; } public function getKeyword(): string { return $this->keyword; } function getExpression(SQL $sql, array &$params): string { $keyword = $this->getKeyword(); $left = $sql->addValue($this->getLeftExp(), $params); $right = $sql->addValue($this->getRightExp(), $params); return "$left $keyword $right"; } }