例子:select * from user where id=1查询id为一的用户select * from user where name like '章%'查询姓张的用户select * from user where age in (12,13,14) and sex='男'查询年龄是12,13,14的男生用户。。。。
比如查询student表里面id等于23的数据:select * from student where id = 23这样子写