问基于ID从2列中查找缺少的组合

EN

CREATE TABLE `your_table` (
  `id_session` int not null,
  `columnstart` varchar(8) NOT NULL,
  `columnend` varchar(8) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `your_table` (`id_session`,`columnstart`, `columnend`) VALUES
(1, 1, 1),
(1, 1, 3),
(1, 2, 1),
(1, 2, 2),
(1, 2, 3),
(2, 1, 1),
(2, 1, 2),
(2, 1, 3),
(2, 2, 1),
(2, 3, 1);

SELECT dt.columnstart, 
       dt.columnend 
FROM 
(
  SELECT t1.columnstart, t2.columnend FROM 
    (SELECT  columnstart FROM your_table where id_session = 2 group by columnstart) AS t1 
    CROSS JOIN 
    (SELECT  columnend FROM your_table where id_session = 2 group by columnend) AS t2 
) AS dt 
LEFT JOIN your_table AS t3 
  ON t3.columnstart = dt.columnstart AND 
     t3.columnend = dt.columnend 
WHERE t3.columnstart IS NULL AND 
      t3.columnend IS NULL