1、创建表且插入数据
create table t1 (
id int,
name varchar(100),
age int,
sex varchar(20),
address varchar(100),
math int,
english int
)engine=innodb;
insert into t1 values(1,"马云",50,"男","北京",66,78),(2,"马化腾",45,"男","北京",80,91),(3,"刘青",40,"女","上海",60,91),(4,"王石",60,"男","深圳",88,58),(5,"马花",67,"男","北京",57,91),(6,"尚杰",50,"男","北京",66,null);
2、比较运算和逻辑运算符符（between..and,in）
SELECT * FROM t1 WHERE age >= 20 && age <=60;
SELECT * FROM t1 WHERE age >= 20 AND age <=60;
SELECT * FROM t1 WHERE age BETWEEN 20 AND 60;
SELECT * FROM t1 WHERE age = 45 OR age = 50 OR age = 90;
SELECT * FROM t1 WHERE age IN (45,50,90);
3、列表运算符（in）
select * from t1 where address in("北京","上海");
4、空值判断（null）
SELECT * FROM t1 WHERE english IS NULL;
5、存在条件（exists）
SELECT age FROM t1 where EXISTS (SELECT age FROM t1 where age BETWEEN 20 AND 60);
1.作者：Syw
2,本文版权归作者所有，欢迎转载，但未经作者同意必须保留此段声明，且在文章页面明显位置给出原文连接，否则保留追究法律责任的权利。
3.如果文中有什么错误，欢迎指出。以免更多的人被误导。
