題目描述:
查找各個部門當前(to_date=‘9999-01-01’)領導當前薪水詳情以及其對應部門編號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
));
思路:
兩張表的內容=inner join 或 join
兩張表需要一個橋樑搭建起來=on
兩張表的to_date條件需要同時滿足需要 and
代碼:
select d.dept_no,d.emp_no,s.salary
from salaries as s inner join dept_manager as d
on s.emp_no = d.emp_no
and
d.to_date='9999-01-01'
and
s.to_date='9999-01-01'
輸出描述: