查找各个部门当前(to_date='9999-01-01')领导当前薪水详情以及其对应部门编号dept_no

查找各个部门当前(to_date=’9999-01-01’)领导当前薪水详情以及其对应部门编号dept_no
CREATE TABLE dept_manager (
dept_no char(4) NOT NULL,
emp_no int(11) NOT NULL,
from_date date NOT NULL,
to_date date NOT NULL,
PRIMARY KEY (emp_no,dept_no));
CREATE TABLE salaries (
emp_no int(11) NOT NULL,
salary int(11) NOT NULL,
from_date date NOT NULL,
to_date date NOT NULL,
PRIMARY KEY (emp_no,from_date));

答案：

select s.* , d.dept_no from salaries as s ,dept_manager as d 
where s.emp_no=d.emp_no 
and s.to_date='9999-01-01' 
and d.to_date='9999-01-01'