模糊查询：LIKE、通配符 %、_

create table studentsd
(

id int,
stu_name nvarchar(20)

);

insert into studentsd
values
(1,N'张三'),
(2,N'张三丰'),
(3,N'张无忌'),
(4,N'李四'),
(5,N'张小凡');

--开头匹配
select * from studentsd
where stu_name like N'张%';

--结尾匹配
select * from studentsd
where stu_name like N'%三';

--中间匹配
select * from studentsd
where stu_name like N'%凡%';

--代表单个字符
select * from studentsd
where stu_name like N'张';

select * from studentsd
where stu_name like N'张_%';

--取反 not like
select * from studentsd
where stu_name not like N'张%';