sql查询——范围查询（区间查询）

 1 --范围查询（区间查询）
 2   --in()
 3   --查询年龄为18,28，38的人   select *from student where age=18 or age=28 or age=38;
 4   select *from student where age in(18,28,38);
 5   --not in
 6   --查询年龄为18,28，38的人   select *from student where not (age=18 or age=28 or age=38);
 7   select *from student where age not in (18,28,38);
 8   --between...and...
 9   --查询12-18的人
10   select *from student where age between 12 and 18;
11   -- not between...and...
12   -- 查询年龄不在12-18的人
13   select *from student where age not between 12 and 18;
14   -- 失败select *from student where age not (between 12 and 18);
15 
16 
17 --判断空
18       -- is null
19       -- 判断年龄是否为空
20       select *from student where age is null;
21       -- is not NULL
22       -- 判断年龄不为空
23       select *from student where age is not null;