mysql比较运算,逻辑运算,范围查询,模糊查询

比较运算 > < = != <> <= >=

逻辑运算 and or not

范围查询 in

模糊查询 like

select distinct age from classes; 将classes表格里age去重

select * from classes where id <= 3; 打印classes表格里id<=3的数据 (<>、!=)除了整形还可以用于datetime

select * from classes where num is(not) null; 打印classes表格里num栏是(否)为null is 和 not 只能用来判断null

select * from student where add_time between '2018-05-08' and '2018-05-10 09:00:00'; 打印student表格里add_time栏里时间在两者之间的数据,between and相当于>=、<=可作用于时间和整形

select name from student where id > 1 and id < 3; 打印student表格里id>1并<3的name栏 and or not 逻辑运算符

select * from student where name like '小%'; 模糊查找 like 打印student表格里姓名栏(字段)里以'小'开头的数据

select * from student where name like '%张%';

select * from student where name like '_明'; 占位匹配 _ 一个下划线代表一个字符

select * from student where id (not) in (1,2,3); 打印student表格里id是(否)在(1,2,3)里的数据，是否在范围内

巴特西