select * from user where userId='105';
select * from user where name like '王%';
select * from user where ename rlike 'a';
select * from user where personId like '110%';
select * from user where credit>400;
select * from user where city='上海';
select * from user where sex='女';
select * from user where credit<300 and sex='男';
select * from user where city='上海' and sex='女';
select city from user;
select * from user where city in ('长沙','深圳');
select * from user where credit between 200 and 400;
select * from user where ename is null;
select * from user where name like '__';
select * from user where ename not rlike 'o';
select * from user where credit not between 200 and 400;