建表
drop table if EXISTS employee; create table employee ( empId int, name varchar(10), supervisor int, salary DECIMAL ); drop table if EXISTS bonus; create table bonus ( empId int, bonus DECIMAL ); insert into employee values(1, 'John', 3, 1000); insert into employee values(2, 'Dan', 3, 2000); insert into employee values(3, 'Brad', null, 4000); insert into employee values(4, 'Thomas', 3, 4000); insert into bonus values(2, 500); insert into bonus values(4, 2000); select e.name, b.bonus from employee e left join bonus b on e.empId = b.empId where IFNULL(b.bonus,0) < 1000