system/Database/MySQLi/Forge.php
protected function _processColumn(array $field): string
	{
		$extra_clause = isset($field['after']) ? ' AFTER ' . $this->db->escapeIdentifiers($field['after']) : '';

		if (empty($extra_clause) && isset($field['first']) && $field['first'] === true)
		{
			$extra_clause = ' FIRST';
		}

		return $this->db->escapeIdentifiers($field['name'])
				. (empty($field['new_name']) ? '' : ' ' . $this->db->escapeIdentifiers($field['new_name']))
				. ' ' . $field['type'] . $field['length']
				. $field['unsigned']
				. $field['null']
				. $field['default']
				. $field['auto_increment']
				. $field['unique']
				. (empty($field['comment']) ? '' : ' COMMENT ' . $field['comment'])
				. $extra_clause;
	}
protected function _processColumn(array $field): string
	{
		$extra_clause = isset($field['after']) ? ' AFTER ' . $this->db->escapeIdentifiers($field['after']) : '';

		if (empty($extra_clause) && isset($field['first']) && $field['first'] === true)
		{
			$extra_clause = ' FIRST';
		}

		return $this->db->escapeIdentifiers($field['name'])
				. (empty($field['new_name']) ? '' : ' ' . $this->db->escapeIdentifiers($field['new_name']))
				. ' ' . $field['type'] . $field['length']
				. $field['unsigned']
				. $field['null']
				. $field['default']
				. $field['auto_increment']
				. $field['unique']
				. (empty($field['comment']) ? '' : ' COMMENT ' . $field['comment'])
				. $extra_clause;
	}
Process column

@param  array $field
@return string