CREATE TABLE `Classes` (
  `class` VARCHAR(255) PRIMARY KEY,
  `type` VARCHAR(2),
  `country`  VARCHAR(255),
  `numGuns` INT,
  `bore` INT,
  `displacement` INT
);

CREATE TABLE `Ships` (
  `name` VARCHAR(255) PRIMARY KEY,
  `class` VARCHAR(255),
  `launched` INT
);

CREATE TABLE `Battles` (
  `name` VARCHAR(255) PRIMARY KEY,
  `date` DATE /* or VARCHAR(255) */
);

CREATE TABLE `Outcomes` (
  `ship` VARCHAR(255),
  `battle` VARCHAR(255),
  `result` VARCHAR(7)
);

ALTER TABLE `Classes` DROP COLUMN `bore`;

ALTER TABLE `Ships` ADD `yard` VARCHAR(255);


SELECT `class`, `country` FROM `Classes` WHERE `bore` >= 16;

SELECT `name` FROM `Ships` WHERE `launched` < 1921;

SELECT `ship` FROM `Outcomes` WHERE `battle` = 'Denmark Strait' AND `result` = 'sunk';

SELECT Ships.name FROM `Ships` JOIN `Classes` ON Ships.class = Classes.class WHERE Ships.launched > 1921 AND Classes.displacement > 35000;