#逻辑运算符 and or not
select * from student where age = 10 or age =11

#关系运算符 
select * from student where age > 10 

#between and			#输出大小在之间的数剧的行
select * from student where age between 10 and 24 #包括两端
select * from student where age between 24 and 10 #小值在前，大值在后，不允许颠倒，否则查不出结果

#观察我们知道表格中有一行数据的的地址如果想输出这行，使用如下代码可以吗？
select * from student where address=null 
#通过运行我们会发现输出的是一条空行

#这时候需要使用到 is
select * from student where address is null
select * from student where address is not null

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select * from student where age between 10 and 24展示如下