
关键词:like % 替换1个或者多个 _ 替换一个
案例: 1.查询姓名中以"小"开始的名字
select name from students where name like "小%";2.查询姓名中有2个字的名字
select name from students where name like "__";3.查询姓名中有至少有2个字的名字
select name from students where name like "__%";关键词:rlike 案例: 1.查询以章开始的姓名
select name from students where name rlike "^章.*";关键词:in 表示在一个非连续的范围内 案例: 1.查询 年龄为18,34的姓名
select name from students where age in (18,34);
--等价于
select name from students where age=18 or age=34;关键词:between and 表示在一个连续的范围内 案例: 1.查询年龄在18到34之间的姓名
select name from students where age between 18 and 34;关键词:null 不区分大小写 案例: 1.查询身高为空的姓名
select name from students where height is NULL;关键词: order by … asc 案例: 1.查询所有信息,按照年龄从小到大排序
select * from students order by age asc;2.查询所有信息,按照年龄从小到大,身高从小到大排序
select * from students order by age asc, height asc;关键词: order by … desc 案例: 1.查询所有信息,按照年龄从大到小排序
select * from students order by age desc;