I am trying to find the second highest salary in each department.
Schema:
CREATE TABLE employees
(
ID int NOT NULL,
NAME char(50) NOT NULL,
departmentid int,
salary int
);
Sample records:
/*departmentid =1 */
INSERT INTO employees VALUES (1, 'Max', 1, 90000);
INSERT INTO employees VALUES (2, 'Joe', 1, 70000);
INSERT INTO employees VALUES (3, 'Randy', 1, 70000);
/*departmentid =2 */
INSERT INTO employees VALUES (4, 'Henry', 2, 80000);
INSERT INTO employees VALUES (5, 'SAM', 2, 60000);
/*departmentid =3 */
INSERT INTO employees VALUES (6, 'Janet', 3, 69000);
My query:
SELECT departmentid,
NAME,
salary
FROM
(
SELECT
departmentid,
NAME,
salary,
Dense_rank()OVER (partition BY departmentid
ORDER BY salary DESC) AS Rank,
Count(1)OVER(partition BY departmentid) AS cnt
FROM
employees
)t
WHERE
t.rank = 2
OR ( t.rank = 1
AND cnt = 1 )
The output I am getting is as below;
departmentid NAME salary
1 Joe 70000
1 Randy 70000
2 SAM 60000
3 Janet 69000
My expected output is
departmentid NAME salary
1 Joe 70000
1 Randy 70000
2 SAM 60000
3 NULL NULL
As there is only one record for departmentid=3, it should return null.
What is wrong with this query? Any other ways to achieve this result?
I've also included a SQL fiddle.
7条答案
按热度按时间3gtaxfhh1#
ROW_NUMBER() and select = 2
dffbzjpn2#
I've used two CTEs .
The first returns a list of every department. You'll need this to ensure departments with less than 2 salaries are included in the final result.
The second ranks each employee within their department.
Finally, I've used a left outer join to maintain the complete list of departments.
Returns
6ojccjat3#
Use a sub query as i wrote here : http://sqlfiddle.com/#!6/bb5e1/26
13z8s7eq4#
If the departmentid having only one row, and if you consider that also. Then
Query
y1aodyip5#
There is also a simple way:
Edit: this returns only the 2nd highest overall
f45qwnt86#
I think you can get correct answer by just removing below code from your code
also main table should be left join from this result to get null in rest of columns
y0u0uwnf7#