Question

这句数据库sql语句如何用exists关键字去写？

表结构如下

数据库是mysql
CREATE TABLE `student` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`stuno` varchar(50) COLLATE utf8_bin DEFAULT NULL,
`stuname` varchar(50) COLLATE utf8_bin DEFAULT NULL,
`course` varchar(50) COLLATE utf8_bin DEFAULT NULL,
`score` double DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

sql语句如下：
DELETE FROM student WHERE id NOT IN (SELECT k.id FROM(SELECT MIN(id) AS id FROM student GROUP BY stuno,stuname,course,score) k);

请将这句话用exists关键字来写

Answer 1

DELETE FROM student WHERE NOT EXISTS(SELECT *FROM(SELECT MIN(id) AS id FROM student GROUP BY stuno,stuname,course,score) k WHERE k.id=student.id);