mysql子查询

ANY SOME

ANY == SOME

SELECT 
	student_id
FROM 
	class_1
WHERE
	score > ANY(SELECT score FROM class_2);
		

ALL

SELECT 
	student_id
FROM 
	class_1
WHERE
	score > ALL(SELECT score FROM class_2);

EXIST

EXIST相当于判断+执行，如果子查询的内容存在，则继续运行外查询，否则不运行。
示例：查询是否存在id=117的学生，如果存在，则查询所有学生的id。

SELECT
	id
FROM
	students
WHERE EXISTS(SELECT id FROM students WHERE id=117);

IN

SELECT
	score
FROM
	students
WHERE id IN (SELECT id FROM student_class_1_good );

带有比较运算符

• <
• <=

• =

• != （已经弃用）
• <>