模糊查询

-- 查询姓刘的同学

-- like 结合　　%（表示0到任意个字符） _(表示一个字符)

select `studentNo`, `studentName` from student where studentName LIKE '刘%'

-- 查询姓刘的同学后面分别只有一个字的，两个字的

select `studentNo`, `studentName` from student where studentName LIKE '刘_'

select `studentNo`, `studentName` from student where studentName LIKE '刘__'

-- 查询姓名中间有一个嘉字的

select `studentNo`, `stundetName` from student where studentName LIKE '%嘉%'

 

-- in

-- 查询1001,1002,1003号

select `studentNo`, `studentName` from student where studentNo IN (1001,1002,1003)

-- 查询在北京的学生

select `studentNo`, `studentName` from student where address IN ('北京', '安徽')

-- null　　not null

select `studentNo`, `studentName` from student where address='' OR adress IS NULL

-- 查询有出生日期的同学

select `studentNo`, `studentName` from student where BornDate !='' OR BornDate IS NOT NULL

-- 查询没有出生日期的同学

select `studentNo`, `studentName` from student where BornDate IS NULL