##(2.3)查询学号是S_1001,S_1002,S_1003的记录
写法一：select * from stu where sid = ‘S_1001‘ or sid = ‘S_1002‘ or sid = ‘S_1003‘;
写法二：select * from stu where sid in (‘S_1001‘, ‘S_1002‘, ‘S_1003‘);
##(2.3)查询学号不是S_1001，S_1001,S_1002,S_1003的记录
select * from stu where sid not in (‘S_1001‘, ‘S_1002‘, ‘S_1003‘);
##(2.4)查询年龄为null的记录
select * from stu where sname is not null;
##(2.5)查询年龄为20-40之间的
方式一:select * from stu where age >=20 and age <=40;
方式二:select * from stu where age between 20 and <= 40;错误
##(2.6)查询性别：非男 学生记录
select * from stu where gender != ‘male‘;
select * from stu where gender <> ‘male‘;
select * from stu where not gender = ‘male‘;
##(2.7)查询名字不为空的学生信息
select * from stu where sname is not null;
##通配符
##查询名字有五个字母构成的 学生记录
select * from stu where sname like ‘______‘;
原文：https://www.cnblogs.com/zsrr/p/14646490.html